diff --git a/build.sbt b/build.sbt
index e90dba2..066fd4d 100644
--- a/build.sbt
+++ b/build.sbt
@@ -8,9 +8,13 @@ scalaVersion := "2.12.8"
 libraryDependencies += "com.github.scopt" %% "scopt" % "4.0.0-RC2"
 
 // AWS SDK
+/// wraps the in-preview Java SDK V2 which is incomplete and doesn't support multi-part uploads
 libraryDependencies += "com.github.j5ik2o" %% "reactive-aws-s3-core" % "1.1.3"
 libraryDependencies += "com.github.j5ik2o" %% "reactive-aws-s3-cats" % "1.1.3"
 
+// AWS SDK - multi-part upload
+libraryDependencies += "com.amazonaws" % "aws-java-sdk-s3" % "1.11.560"
+
 // Logging
 libraryDependencies += "com.typesafe.scala-logging" %% "scala-logging" % "3.9.2"
 libraryDependencies += "org.slf4j" % "slf4j-log4j12" % "1.7.26"
diff --git a/src/main/scala/net/kemitix/s3thorp/ActionSubmitter.scala b/src/main/scala/net/kemitix/s3thorp/ActionSubmitter.scala
index 044894f..24c22ab 100644
--- a/src/main/scala/net/kemitix/s3thorp/ActionSubmitter.scala
+++ b/src/main/scala/net/kemitix/s3thorp/ActionSubmitter.scala
@@ -13,7 +13,7 @@ trait ActionSubmitter
       action match {
         case ToUpload(file) =>
           log4(s"    Upload: ${file.relative}")
-          upload(file, c.bucket)
+          upload(file, c.bucket, 1)
         case ToCopy(sourceKey, hash, targetKey) =>
           log4(s"      Copy: $sourceKey => $targetKey")
           copy(c.bucket, sourceKey, hash, targetKey)
diff --git a/src/main/scala/net/kemitix/s3thorp/Config.scala b/src/main/scala/net/kemitix/s3thorp/Config.scala
index 9eb7350..b9a93a9 100644
--- a/src/main/scala/net/kemitix/s3thorp/Config.scala
+++ b/src/main/scala/net/kemitix/s3thorp/Config.scala
@@ -6,7 +6,10 @@ case class Config(bucket: Bucket = Bucket(""),
                   prefix: RemoteKey = RemoteKey(""),
                   verbose: Int = 1,
                   filters: Seq[Filter] = List(),
+                  multiPartThreshold: Long = 1024 * 1024 * 5,
+                  maxRetries: Int = 3,
                   source: File
                ) {
   require(source.isDirectory, s"Source must be a directory: $source")
+  require(multiPartThreshold >= 1024 * 1024 * 5, s"Threshold for multi-part upload is 5Mb: '$multiPartThreshold'")
 }
diff --git a/src/main/scala/net/kemitix/s3thorp/MD5HashGenerator.scala b/src/main/scala/net/kemitix/s3thorp/MD5HashGenerator.scala
index 56491cd..803dde2 100644
--- a/src/main/scala/net/kemitix/s3thorp/MD5HashGenerator.scala
+++ b/src/main/scala/net/kemitix/s3thorp/MD5HashGenerator.scala
@@ -6,15 +6,30 @@ import java.security.{DigestInputStream, MessageDigest}
 trait MD5HashGenerator
   extends Logging {
 
-  def md5File(file: File)(implicit c: Config): MD5Hash =  {
-    log5(s"md5file:reading:${file.length}:$file")
-    val buffer = new Array[Byte](8192)
-    val md5 = MessageDigest.getInstance("MD5")
-    val dis = new DigestInputStream(new FileInputStream(file), md5)
-    try { while (dis.read(buffer) != -1) { } } finally { dis.close() }
-    val hash = md5.digest.map("%02x".format(_)).mkString
-    log5(s"md5file:generated:$hash:$file")
-    MD5Hash(hash)
+  def md5File(file: File)
+             (implicit c: Config): MD5Hash =  {
+    val hash = md5FilePart(file, 0, file.length)
+    hash
+  }
+
+  def md5FilePart(file: File,
+                  offset: Long,
+                  size: Long)
+                 (implicit c: Config): MD5Hash = {
+    log5(s"md5:reading:offset $offset:size $size:$file")
+    val fis = new FileInputStream(file)
+    fis skip offset
+    val buffer = new Array[Byte](size.toInt)
+    fis read buffer
+    val hash = md5PartBody(buffer)
+    log5(s"md5:generated:${hash.hash}")
+    hash
+  }
+
+  def md5PartBody(partBody: Array[Byte]): MD5Hash = {
+    val md5 = MessageDigest getInstance "MD5"
+    md5 update partBody
+    MD5Hash((md5.digest map ("%02x" format _)).mkString)
   }
 
 }
diff --git a/src/main/scala/net/kemitix/s3thorp/S3Action.scala b/src/main/scala/net/kemitix/s3thorp/S3Action.scala
index 903dc9e..114e5d8 100644
--- a/src/main/scala/net/kemitix/s3thorp/S3Action.scala
+++ b/src/main/scala/net/kemitix/s3thorp/S3Action.scala
@@ -24,6 +24,10 @@ case class DeleteS3Action(remoteKey: RemoteKey) extends S3Action {
   override val order: Int = 3
 }
 
+case class ErroredS3Action(remoteKey: RemoteKey, e: Throwable) extends S3Action {
+  override val order: Int = 10
+}
+
 object S3Action {
   implicit def ord[A <: S3Action]: Ordering[A] = Ordering.by(_.order)
 }
diff --git a/src/main/scala/net/kemitix/s3thorp/Sync.scala b/src/main/scala/net/kemitix/s3thorp/Sync.scala
index 6c06adf..9e3b5cf 100644
--- a/src/main/scala/net/kemitix/s3thorp/Sync.scala
+++ b/src/main/scala/net/kemitix/s3thorp/Sync.scala
@@ -38,8 +38,10 @@ class Sync(s3Client: S3Client)
     ioActions.flatMap { actions => IO { actions.sorted } }
 
   override def upload(localFile: LocalFile,
-                      bucket: Bucket)(implicit c: Config): IO[UploadS3Action] =
-    s3Client.upload(localFile, bucket)
+                      bucket: Bucket,
+                      tryCount: Int)
+                     (implicit c: Config): IO[S3Action] =
+    s3Client.upload(localFile, bucket, tryCount)
 
   override def copy(bucket: Bucket,
                     sourceKey: RemoteKey,
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/CancellableMultiPartUpload.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/CancellableMultiPartUpload.scala
new file mode 100644
index 0000000..60eb2bd
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/CancellableMultiPartUpload.scala
@@ -0,0 +1,4 @@
+package net.kemitix.s3thorp.awssdk
+
+case class CancellableMultiPartUpload(e: Throwable,
+                                      uploadId: String) extends Exception(e)
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/QuoteStripper.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/QuoteStripper.scala
new file mode 100644
index 0000000..28a9d0a
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/QuoteStripper.scala
@@ -0,0 +1,7 @@
+package net.kemitix.s3thorp.awssdk
+
+trait QuoteStripper {
+
+  def stripQuotes: Char => Boolean = _ != '"'
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3Client.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3Client.scala
index 9956a11..39b83f2 100644
--- a/src/main/scala/net/kemitix/s3thorp/awssdk/S3Client.scala
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3Client.scala
@@ -19,8 +19,9 @@ trait S3Client {
                  )(implicit c: Config): IO[S3ObjectsData]
 
   def upload(localFile: LocalFile,
-             bucket: Bucket
-            )(implicit c: Config): IO[UploadS3Action]
+             bucket: Bucket,
+             tryCount: Int
+            )(implicit c: Config): IO[S3Action]
 
   def copy(bucket: Bucket,
            sourceKey: RemoteKey,
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientCopier.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientCopier.scala
new file mode 100644
index 0000000..20e7a7a
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientCopier.scala
@@ -0,0 +1,28 @@
+package net.kemitix.s3thorp.awssdk
+
+import cats.effect.IO
+import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import net.kemitix.s3thorp.{Bucket, Config, CopyS3Action, MD5Hash, RemoteKey}
+import software.amazon.awssdk.services.s3.model.CopyObjectRequest
+
+private class S3ClientCopier(s3Client: S3CatsIOClient)
+  extends S3ClientLogging {
+
+  def copy(bucket: Bucket,
+           sourceKey: RemoteKey,
+           hash: MD5Hash,
+           targetKey: RemoteKey)
+          (implicit c: Config): IO[CopyS3Action] = {
+    val request = CopyObjectRequest.builder
+      .bucket(bucket.name)
+      .copySource(s"${bucket.name}/${sourceKey.key}")
+      .copySourceIfMatch(hash.hash)
+      .key(targetKey.key).build
+    s3Client.copyObject(request)
+      .bracket(
+        logCopyStart(bucket, sourceKey, targetKey))(
+        logCopyFinish(bucket, sourceKey,targetKey))
+      .map(_ => CopyS3Action(targetKey))
+  }
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientDeleter.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientDeleter.scala
new file mode 100644
index 0000000..7c6d6d1
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientDeleter.scala
@@ -0,0 +1,24 @@
+package net.kemitix.s3thorp.awssdk
+
+import cats.effect.IO
+import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import net.kemitix.s3thorp.{Bucket, Config, DeleteS3Action, RemoteKey}
+import software.amazon.awssdk.services.s3.model.DeleteObjectRequest
+
+private class S3ClientDeleter(s3Client: S3CatsIOClient)
+  extends S3ClientLogging {
+
+  def delete(bucket: Bucket,
+             remoteKey: RemoteKey)
+            (implicit c: Config): IO[DeleteS3Action] = {
+    val request = DeleteObjectRequest.builder
+      .bucket(bucket.name)
+      .key(remoteKey.key).build
+    s3Client.deleteObject(request)
+      .bracket(
+        logDeleteStart(bucket, remoteKey))(
+        logDeleteFinish(bucket, remoteKey))
+      .map(_ => DeleteS3Action(remoteKey))
+  }
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManager.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManager.scala
new file mode 100644
index 0000000..8966e10
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManager.scala
@@ -0,0 +1,27 @@
+package net.kemitix.s3thorp.awssdk
+import cats.effect.IO
+import com.amazonaws.services.s3.transfer.TransferManager
+import net.kemitix.s3thorp._
+
+class S3ClientMultiPartTransferManager(transferManager: TransferManager)
+  extends S3ClientUploader
+    with S3ClientMultiPartUploaderLogging {
+
+  def accepts(localFile: LocalFile)
+             (implicit c: Config): Boolean =
+    localFile.file.length >= c.multiPartThreshold
+
+  override
+  def upload(localFile: LocalFile,
+             bucket: Bucket,
+             tryCount: Int)
+            (implicit c: Config): IO[S3Action] = {
+    IO {
+      logMultiPartUploadStart(localFile, tryCount)
+      val result = transferManager.upload(bucket.name, localFile.remoteKey.key, localFile.file)
+        .waitForUploadResult()
+      logMultiPartUploadFinished(localFile)
+      UploadS3Action(RemoteKey(result.getKey), MD5Hash(result.getETag))
+    }
+  }
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploader.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploader.scala
new file mode 100644
index 0000000..b088c1d
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploader.scala
@@ -0,0 +1,145 @@
+package net.kemitix.s3thorp.awssdk
+
+import scala.collection.JavaConverters._
+import cats.effect.IO
+import cats.implicits._
+import com.amazonaws.services.s3.AmazonS3
+import com.amazonaws.services.s3.model.{AbortMultipartUploadRequest, AmazonS3Exception, CompleteMultipartUploadRequest, CompleteMultipartUploadResult, InitiateMultipartUploadRequest, InitiateMultipartUploadResult, PartETag, UploadPartRequest, UploadPartResult}
+import net.kemitix.s3thorp._
+
+import scala.util.control.NonFatal
+
+private class S3ClientMultiPartUploader(s3Client: AmazonS3)
+  extends S3ClientUploader
+    with S3ClientMultiPartUploaderLogging
+    with MD5HashGenerator
+    with QuoteStripper {
+
+  def accepts(localFile: LocalFile)
+             (implicit c: Config): Boolean =
+    localFile.file.length >= c.multiPartThreshold
+
+  def createUpload(bucket: Bucket, localFile: LocalFile)
+                  (implicit c: Config): IO[InitiateMultipartUploadResult] = {
+    logMultiPartUploadInitiate(localFile)
+    IO(s3Client initiateMultipartUpload createUploadRequest(bucket, localFile))
+  }
+
+  def createUploadRequest(bucket: Bucket, localFile: LocalFile) =
+    new InitiateMultipartUploadRequest(
+      bucket.name,
+      localFile.remoteKey.key)
+
+  def parts(localFile: LocalFile,
+            response: InitiateMultipartUploadResult)
+           (implicit c: Config): IO[Stream[UploadPartRequest]] = {
+    val fileSize = localFile.file.length
+    val maxParts = 1024 // arbitrary, supports upto 10,000 (I, think)
+    val threshold = c.multiPartThreshold
+    val nParts = Math.min((fileSize / threshold) + 1, maxParts).toInt
+    val partSize = fileSize / nParts
+    val maxUpload = nParts * partSize
+
+    IO {
+      require(fileSize <= maxUpload,
+        s"File (${localFile.file.getPath}) size ($fileSize) exceeds upload limit: $maxUpload")
+      logMultiPartUploadPartsDetails(localFile, nParts, partSize)
+      for {
+        partNumber <- (1 to nParts).toStream
+        offSet = (partNumber - 1) * partSize
+        chunkSize = Math.min(fileSize - offSet, partSize)
+        partHash = md5FilePart(localFile.file, offSet, chunkSize)
+        _ = logMultiPartUploadPartDetails(localFile, partNumber, partHash)
+        uploadPartRequest = createUploadPartRequest(localFile, response, partNumber, chunkSize, partHash)
+      } yield uploadPartRequest
+    }
+  }
+
+  private def createUploadPartRequest(localFile: LocalFile,
+                                      response: InitiateMultipartUploadResult,
+                                      partNumber: Int,
+                                      chunkSize: Long,
+                                      partHash: MD5Hash)
+                                     (implicit c: Config) = {
+    new UploadPartRequest()
+      .withBucketName(c.bucket.name)
+      .withKey(localFile.remoteKey.key)
+      .withUploadId(response.getUploadId)
+      .withPartNumber(partNumber)
+      .withPartSize(chunkSize)
+      .withMD5Digest(partHash.hash)
+      .withFile(localFile.file)
+      .withFileOffset((partNumber - 1) * chunkSize)
+  }
+
+  def uploadPart(localFile: LocalFile)
+                (implicit c: Config): UploadPartRequest => IO[UploadPartResult] =
+    partRequest => {
+      logMultiPartUploadPart(localFile, partRequest)
+      IO(s3Client.uploadPart(partRequest))
+        .handleErrorWith{
+          case error: AmazonS3Exception => {
+          logMultiPartUploadPartError(localFile, partRequest, error)
+          IO.raiseError(CancellableMultiPartUpload(error, partRequest.getUploadId))
+        }}
+    }
+
+  def uploadParts(localFile: LocalFile,
+                  parts: Stream[UploadPartRequest])
+                 (implicit c: Config): IO[Stream[UploadPartResult]] =
+    (parts map uploadPart(localFile)).sequence
+
+  def completeUpload(createUploadResponse: InitiateMultipartUploadResult,
+                     uploadPartResponses: Stream[UploadPartResult],
+                     localFile: LocalFile)
+                    (implicit c: Config): IO[CompleteMultipartUploadResult] = {
+    logMultiPartUploadCompleted(createUploadResponse, uploadPartResponses, localFile)
+    IO(s3Client completeMultipartUpload createCompleteRequest(createUploadResponse, uploadPartResponses.toList))
+  }
+
+  def createCompleteRequest(createUploadResponse: InitiateMultipartUploadResult,
+                            uploadPartResult: List[UploadPartResult]) = {
+    new CompleteMultipartUploadRequest()
+      .withBucketName(createUploadResponse.getBucketName)
+      .withKey(createUploadResponse.getKey)
+      .withUploadId(createUploadResponse.getUploadId)
+      .withPartETags(uploadPartResult.asJava)
+  }
+
+  def cancel(uploadId: String, localFile: LocalFile)
+            (implicit c: Config): IO[Unit] = {
+    logMultiPartUploadCancelling(localFile)
+    IO(s3Client abortMultipartUpload createAbortRequest(uploadId, localFile))
+  }
+
+  def createAbortRequest(uploadId: String,
+                         localFile: LocalFile)
+                        (implicit c: Config): AbortMultipartUploadRequest =
+    new AbortMultipartUploadRequest(c.bucket.name, localFile.remoteKey.key, uploadId)
+
+  override def upload(localFile: LocalFile,
+                      bucket: Bucket,
+                      tryCount: Int)
+                     (implicit c: Config): IO[S3Action] = {
+    logMultiPartUploadStart(localFile, tryCount)
+
+    (for {
+      createUploadResponse <- createUpload(bucket, localFile)
+      parts <- parts(localFile, createUploadResponse)
+      uploadPartResponses <- uploadParts(localFile, parts)
+      completedUploadResponse <- completeUpload(createUploadResponse, uploadPartResponses, localFile)
+    } yield completedUploadResponse)
+      .map(_.getETag)
+      .map(_ filter stripQuotes)
+      .map(MD5Hash)
+      .map(UploadS3Action(localFile.remoteKey, _))
+      .handleErrorWith {
+        case CancellableMultiPartUpload(e, uploadId) =>
+          if (tryCount >= c.maxRetries) IO(logErrorCancelling(e, localFile)) *> cancel(uploadId, localFile) *> IO.pure(ErroredS3Action(localFile.remoteKey, e))
+          else IO(logErrorRetrying(e, localFile, tryCount)) *> upload(localFile, bucket, tryCount + 1)
+        case NonFatal(e) =>
+          if (tryCount >= c.maxRetries) IO(logErrorUnknown(e, localFile)) *> IO.pure(ErroredS3Action(localFile.remoteKey, e))
+          else IO(logErrorRetrying(e, localFile, tryCount)) *> upload(localFile, bucket, tryCount + 1)
+      }
+  }
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderLogging.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderLogging.scala
new file mode 100644
index 0000000..7031c86
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderLogging.scala
@@ -0,0 +1,77 @@
+package net.kemitix.s3thorp.awssdk
+
+import com.amazonaws.services.s3.model.{AmazonS3Exception, InitiateMultipartUploadResult, UploadPartRequest, UploadPartResult}
+import net.kemitix.s3thorp.{Config, LocalFile, MD5Hash}
+
+trait S3ClientMultiPartUploaderLogging
+  extends S3ClientLogging {
+
+  private val prefix = "multi-part upload"
+
+  def logMultiPartUploadStart(localFile: LocalFile,
+                              tryCount: Int)
+                             (implicit c: Config): Unit =
+    log4(s"$prefix:upload:try $tryCount: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadFinished(localFile: LocalFile)
+                                (implicit c: Config): Unit =
+    log4(s"$prefix:upload:finished: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadInitiate(localFile: LocalFile)
+                                (implicit c: Config): Unit =
+    log5(s"$prefix:initiating: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadPartsDetails(localFile: LocalFile,
+                                     nParts: Int,
+                                     partSize: Long)
+                                    (implicit c: Config): Unit =
+    log5(s"$prefix:parts $nParts:each $partSize: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadPartDetails(localFile: LocalFile,
+                                    partNumber: Int,
+                                    partHash: MD5Hash)
+                                   (implicit c: Config): Unit =
+    log5(s"$prefix:part $partNumber:hash ${partHash.hash}: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadPart(localFile: LocalFile,
+                             partRequest: UploadPartRequest)
+                            (implicit c: Config): Unit =
+    log5(s"$prefix:sending:part ${partRequest.getPartNumber}: ${partRequest.getMd5Digest}: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadPartDone(localFile: LocalFile,
+                                 partRequest: UploadPartRequest,
+                                 result: UploadPartResult)
+                                (implicit c: Config): Unit =
+    log5(s"$prefix:sent:part ${partRequest.getPartNumber}: ${result.getPartETag}: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadPartError(localFile: LocalFile,
+                                  partRequest: UploadPartRequest,
+                                  error: AmazonS3Exception)
+                                 (implicit c: Config): Unit = {
+    val returnedMD5Hash = error.getAdditionalDetails.get("Content-MD5")
+    warn(s"$prefix:error:part ${partRequest.getPartNumber}:ret-hash $returnedMD5Hash: ${localFile.remoteKey.key}")
+  }
+
+  def logMultiPartUploadCompleted(createUploadResponse: InitiateMultipartUploadResult,
+                                  uploadPartResponses: Stream[UploadPartResult],
+                                  localFile: LocalFile)
+                                 (implicit c: Config): Unit =
+    log4(s"$prefix:completed:parts ${uploadPartResponses.size}: ${localFile.remoteKey.key}")
+
+  def logMultiPartUploadCancelling(localFile: LocalFile)
+                                  (implicit c: Config): Unit =
+    warn(s"$prefix:cancelling: ${localFile.remoteKey.key}")
+
+  def logErrorRetrying(e: Throwable, localFile: LocalFile, tryCount: Int)
+                      (implicit c: Config): Unit =
+    warn(s"$prefix:retry:error ${e.getMessage}: ${localFile.remoteKey.key}")
+
+  def logErrorCancelling(e: Throwable, localFile: LocalFile)
+                        (implicit c: Config) : Unit =
+    error(s"$prefix:cancelling:error ${e.getMessage}: ${localFile.remoteKey.key}")
+
+  def logErrorUnknown(e: Throwable, localFile: LocalFile)
+                     (implicit c: Config): Unit =
+    error(s"$prefix:unknown:error $e: ${localFile.remoteKey.key}")
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientObjectLister.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientObjectLister.scala
new file mode 100644
index 0000000..bab10b2
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientObjectLister.scala
@@ -0,0 +1,38 @@
+package net.kemitix.s3thorp.awssdk
+
+import cats.effect.IO
+import net.kemitix.s3thorp.{Bucket, Config, HashModified, LastModified, MD5Hash, RemoteKey}
+import software.amazon.awssdk.services.s3.model.{ListObjectsV2Request, S3Object}
+import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import scala.collection.JavaConverters._
+
+private class S3ClientObjectLister(s3Client: S3CatsIOClient)
+  extends S3ClientLogging
+    with S3ObjectsByHash
+    with QuoteStripper {
+
+  def listObjects(bucket: Bucket,
+                           prefix: RemoteKey)
+                          (implicit c: Config): IO[S3ObjectsData] = {
+    val request = ListObjectsV2Request.builder
+      .bucket(bucket.name)
+      .prefix(prefix.key).build
+    s3Client.listObjectsV2(request)
+      .bracket(
+        logListObjectsStart(bucket, prefix))(
+        logListObjectsFinish(bucket,prefix))
+      .map(_.contents)
+      .map(_.asScala)
+      .map(_.toStream)
+      .map(os => S3ObjectsData(byHash(os), byKey(os)))
+  }
+
+  private def byKey(os: Stream[S3Object]) =
+    os.map { o => {
+      val remoteKey = RemoteKey(o.key)
+      val hash = MD5Hash(o.eTag() filter stripQuotes)
+      val lastModified = LastModified(o.lastModified())
+      (remoteKey, HashModified(hash, lastModified))
+    }}.toMap
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientPutObjectUploader.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientPutObjectUploader.scala
new file mode 100644
index 0000000..283922b
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientPutObjectUploader.scala
@@ -0,0 +1,34 @@
+package net.kemitix.s3thorp.awssdk
+
+import cats.effect.IO
+import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import net.kemitix.s3thorp.{Bucket, Config, LocalFile, MD5Hash, UploadS3Action}
+import software.amazon.awssdk.core.async.AsyncRequestBody
+import software.amazon.awssdk.services.s3.model.PutObjectRequest
+
+private class S3ClientPutObjectUploader(s3Client: S3CatsIOClient)
+  extends S3ClientUploader
+    with S3ClientLogging
+    with QuoteStripper {
+
+  override def accepts(localFile: LocalFile)(implicit c: Config): Boolean = true
+
+  override
+  def upload(localFile: LocalFile,
+             bucket: Bucket,
+             tryCount: Int)
+            (implicit c: Config): IO[UploadS3Action] = {
+    val request = PutObjectRequest.builder
+      .bucket(bucket.name)
+      .key(localFile.remoteKey.key).build
+    val body = AsyncRequestBody.fromFile(localFile.file)
+    s3Client.putObject(request, body)
+      .bracket(
+        logUploadStart(localFile, bucket))(
+        logUploadFinish(localFile, bucket))
+      .map(_.eTag)
+      .map(_ filter stripQuotes)
+      .map(MD5Hash)
+      .map(UploadS3Action(localFile.remoteKey, _))
+  }
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientUploader.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientUploader.scala
new file mode 100644
index 0000000..c9e6964
--- /dev/null
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/S3ClientUploader.scala
@@ -0,0 +1,16 @@
+package net.kemitix.s3thorp.awssdk
+
+import cats.effect.IO
+import net.kemitix.s3thorp.{Bucket, Config, LocalFile, S3Action}
+
+trait S3ClientUploader {
+
+  def accepts(localFile: LocalFile)
+             (implicit c: Config): Boolean
+
+  def upload(localFile: LocalFile,
+             bucket: Bucket,
+             tryCount: Int)
+            (implicit c: Config): IO[S3Action]
+
+}
diff --git a/src/main/scala/net/kemitix/s3thorp/awssdk/ThorpS3Client.scala b/src/main/scala/net/kemitix/s3thorp/awssdk/ThorpS3Client.scala
index dfa8a97..7df1b15 100644
--- a/src/main/scala/net/kemitix/s3thorp/awssdk/ThorpS3Client.scala
+++ b/src/main/scala/net/kemitix/s3thorp/awssdk/ThorpS3Client.scala
@@ -1,89 +1,49 @@
 package net.kemitix.s3thorp.awssdk
 
 import cats.effect.IO
+import com.amazonaws.services.s3.transfer.TransferManagerBuilder
+import com.amazonaws.services.s3.{AmazonS3Client, AmazonS3ClientBuilder}
 import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
 import net.kemitix.s3thorp._
-import software.amazon.awssdk.core.async.AsyncRequestBody
 import software.amazon.awssdk.services.s3.model.{Bucket => _, _}
 
-import scala.collection.JavaConverters._
-
 private class ThorpS3Client(s3Client: S3CatsIOClient)
   extends S3Client
-    with S3ObjectsByHash
-    with S3ClientLogging {
+    with S3ClientLogging
+    with QuoteStripper {
+
+  lazy val amazonS3Client = AmazonS3ClientBuilder.defaultClient
+  lazy val amazonS3TransferManager = TransferManagerBuilder.defaultTransferManager
+  lazy val objectLister = new S3ClientObjectLister(s3Client)
+  lazy val copier = new S3ClientCopier(s3Client)
+  lazy val uploader = new S3ClientPutObjectUploader(s3Client)
+  lazy val multiPartUploader = new S3ClientMultiPartTransferManager(amazonS3TransferManager)
+  lazy val deleter = new S3ClientDeleter(s3Client)
 
   override def listObjects(bucket: Bucket,
                            prefix: RemoteKey)
-                          (implicit c: Config): IO[S3ObjectsData] = {
-    val request = ListObjectsV2Request.builder
-      .bucket(bucket.name)
-      .prefix(prefix.key).build
-    s3Client.listObjectsV2(request)
-      .bracket(
-        logListObjectsStart(bucket, prefix))(
-        logListObjectsFinish(bucket,prefix))
-      .map(_.contents)
-      .map(_.asScala)
-      .map(_.toStream)
-      .map(os => S3ObjectsData(byHash(os), byKey(os)))
-  }
+                          (implicit c: Config): IO[S3ObjectsData] =
+    objectLister.listObjects(bucket, prefix)
 
-  private def byKey(os: Stream[S3Object]) =
-    os.map { o => {
-      val remoteKey = RemoteKey(o.key)
-      val hash = MD5Hash(o.eTag() filter stripQuotes)
-      val lastModified = LastModified(o.lastModified())
-      (remoteKey, HashModified(hash, lastModified))
-    }}.toMap
-
-  override def upload(localFile: LocalFile,
-                      bucket: Bucket)
-                     (implicit c: Config): IO[UploadS3Action] = {
-    val request = PutObjectRequest.builder
-      .bucket(bucket.name)
-      .key(localFile.remoteKey.key).build
-    val body = AsyncRequestBody.fromFile(localFile.file)
-    s3Client.putObject(request, body)
-      .bracket(
-        logUploadStart(localFile, bucket))(
-        logUploadFinish(localFile, bucket))
-      .map(_.eTag)
-      .map(_ filter stripQuotes)
-      .map(MD5Hash)
-      .map(UploadS3Action(localFile.remoteKey, _))
-  }
-
-  private def stripQuotes: Char => Boolean = _ != '"'
 
   override def copy(bucket: Bucket,
                     sourceKey: RemoteKey,
                     hash: MD5Hash,
                     targetKey: RemoteKey)
-                   (implicit c: Config): IO[CopyS3Action] = {
-    val request = CopyObjectRequest.builder
-      .bucket(bucket.name)
-      .copySource(s"${bucket.name}/${sourceKey.key}")
-      .copySourceIfMatch(hash.hash)
-      .key(targetKey.key).build
-    s3Client.copyObject(request)
-      .bracket(
-        logCopyStart(bucket, sourceKey, targetKey))(
-        logCopyFinish(bucket, sourceKey,targetKey))
-      .map(_ => CopyS3Action(targetKey))
-  }
+                   (implicit c: Config): IO[CopyS3Action] =
+    copier.copy(bucket, sourceKey,hash, targetKey)
+
+
+  override def upload(localFile: LocalFile,
+                      bucket: Bucket,
+                      tryCount: Int)
+                     (implicit c: Config): IO[S3Action] =
+    if (multiPartUploader.accepts(localFile)) multiPartUploader.upload(localFile, bucket, 1)
+    else uploader.upload(localFile, bucket, tryCount)
 
   override def delete(bucket: Bucket,
                       remoteKey: RemoteKey)
-                     (implicit c: Config): IO[DeleteS3Action] = {
-    val request = DeleteObjectRequest.builder
-      .bucket(bucket.name)
-      .key(remoteKey.key).build
-    s3Client.deleteObject(request)
-      .bracket(
-        logDeleteStart(bucket, remoteKey))(
-        logDeleteFinish(bucket, remoteKey))
-      .map(_ => DeleteS3Action(remoteKey))
-  }
+                     (implicit c: Config): IO[DeleteS3Action] =
+    deleter.delete(bucket, remoteKey)
 
 }
diff --git a/src/test/resources/net/kemitix/s3thorp/big-file b/src/test/resources/net/kemitix/s3thorp/big-file
new file mode 100644
index 0000000..a8350a9
Binary files /dev/null and b/src/test/resources/net/kemitix/s3thorp/big-file differ
diff --git a/src/test/resources/net/kemitix/s3thorp/small-file b/src/test/resources/net/kemitix/s3thorp/small-file
new file mode 100644
index 0000000..b0abe58
Binary files /dev/null and b/src/test/resources/net/kemitix/s3thorp/small-file differ
diff --git a/src/test/scala/net/kemitix/s3thorp/DummyS3Client.scala b/src/test/scala/net/kemitix/s3thorp/DummyS3Client.scala
index 4bced54..768db94 100644
--- a/src/test/scala/net/kemitix/s3thorp/DummyS3Client.scala
+++ b/src/test/scala/net/kemitix/s3thorp/DummyS3Client.scala
@@ -6,7 +6,8 @@ import net.kemitix.s3thorp.awssdk.{S3ObjectsData, S3Client}
 trait DummyS3Client extends S3Client {
 
   override def upload(localFile: LocalFile,
-                      bucket: Bucket
+                      bucket: Bucket,
+                      tryCount: Int
                      )(implicit c: Config): IO[UploadS3Action] = ???
 
   override def copy(bucket: Bucket,
diff --git a/src/test/scala/net/kemitix/s3thorp/MD5HashGeneratorTest.scala b/src/test/scala/net/kemitix/s3thorp/MD5HashGeneratorTest.scala
new file mode 100644
index 0000000..5636c37
--- /dev/null
+++ b/src/test/scala/net/kemitix/s3thorp/MD5HashGeneratorTest.scala
@@ -0,0 +1,58 @@
+package net.kemitix.s3thorp
+
+import java.nio.file.Files
+
+class MD5HashGeneratorTest extends UnitTest {
+
+  private val source = Resource(this, "upload")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+
+  new MD5HashGenerator {
+    describe("read a small file (smaller than buffer)") {
+      val file = Resource(this, "upload/root-file")
+      it("should generate the correct hash") {
+        val expected = MD5Hash("a3a6ac11a0eb577b81b3bb5c95cc8a6e")
+        val result = md5File(file)
+        assertResult(expected)(result)
+      }
+    }
+    describe("read a buffer") {
+      val file = Resource(this, "upload/root-file")
+      val buffer: Array[Byte] = Files.readAllBytes(file.toPath)
+      it("should generate the correct hash") {
+        val expected = MD5Hash("a3a6ac11a0eb577b81b3bb5c95cc8a6e")
+        val result = md5PartBody(buffer)
+        assertResult(expected)(result)
+      }
+    }
+    describe("read a large file (bigger than buffer)") {
+      val file = Resource(this, "big-file")
+      it("should generate the correct hash") {
+        val expected = MD5Hash("b1ab1f7680138e6db7309200584e35d8")
+        val result = md5File(file)
+        assertResult(expected)(result)
+      }
+    }
+    describe("read part of a file") {
+      val file = Resource(this, "big-file")
+      val halfFileLength = file.length / 2
+      assertResult(file.length)(halfFileLength * 2)
+      describe("when starting at the beginning of the file") {
+        it("should generate the correct hash") {
+          val expected = MD5Hash("aadf0d266cefe0fcdb241a51798d74b3")
+          val result = md5FilePart(file, 0, halfFileLength)
+          assertResult(expected)(result)
+        }
+      }
+      describe("when starting in the middle of the file") {
+        it("should generate the correct hash") {
+          val expected = MD5Hash("16e08d53ca36e729d808fd5e4f7e35dc")
+          val result = md5FilePart(file, halfFileLength, halfFileLength)
+          assertResult(expected)(result)
+        }
+      }
+    }
+  }
+
+}
diff --git a/src/test/scala/net/kemitix/s3thorp/SyncSuite.scala b/src/test/scala/net/kemitix/s3thorp/SyncSuite.scala
index f0399d2..723d9e8 100644
--- a/src/test/scala/net/kemitix/s3thorp/SyncSuite.scala
+++ b/src/test/scala/net/kemitix/s3thorp/SyncSuite.scala
@@ -29,14 +29,17 @@ class SyncSuite
       val md5Hash = MD5Hash("the-hash")
       val testLocalFile = aLocalFile("file", md5Hash, source, generateKey(source, prefix))
       val sync = new Sync(new S3Client with DummyS3Client {
-        override def upload(localFile: LocalFile, bucket: Bucket)(implicit c: Config) = IO {
+        override def upload(localFile: LocalFile,
+                            bucket: Bucket,
+                            tryCount: Int)
+                           (implicit c: Config) = IO {
           assert(bucket == testBucket)
           UploadS3Action(localFile.remoteKey, md5Hash)
         }
       })
       it("delegates unmodified to the S3Client") {
         assertResult(UploadS3Action(RemoteKey(prefix.key + "/file"), md5Hash))(
-          sync.upload(testLocalFile, testBucket).
+          sync.upload(testLocalFile, testBucket, 1).
             unsafeRunSync())
       }
     }
@@ -177,7 +180,8 @@ class SyncSuite
     override def listObjects(bucket: Bucket, prefix: RemoteKey)(implicit c: Config) = IO {s3ObjectsData}
 
     override def upload(localFile: LocalFile,
-                        bucket: Bucket
+                        bucket: Bucket,
+                        tryCount: Int
                        )(implicit c: Config) = IO {
       if (bucket == testBucket)
         uploadsRecord += (localFile.relative.toString -> localFile.remoteKey)
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/MyAmazonS3Client.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/MyAmazonS3Client.scala
new file mode 100644
index 0000000..061cb8b
--- /dev/null
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/MyAmazonS3Client.scala
@@ -0,0 +1,375 @@
+package net.kemitix.s3thorp.awssdk
+
+import java.io.{File, InputStream}
+import java.net.URL
+import java.util
+import java.util.Date
+
+import com.amazonaws.{AmazonWebServiceRequest, HttpMethod}
+import com.amazonaws.regions.Region
+import com.amazonaws.services.s3.model.analytics.AnalyticsConfiguration
+import com.amazonaws.services.s3.model.inventory.InventoryConfiguration
+import com.amazonaws.services.s3.{AmazonS3, S3ClientOptions, S3ResponseMetadata, model}
+import com.amazonaws.services.s3.model.metrics.MetricsConfiguration
+import com.amazonaws.services.s3.model._
+import com.amazonaws.services.s3.waiters.AmazonS3Waiters
+
+class MyAmazonS3Client extends AmazonS3 {
+  override def setEndpoint(endpoint: String): Unit = ???
+
+  override def setRegion(region: Region): Unit = ???
+
+  override def setS3ClientOptions(clientOptions: S3ClientOptions): Unit = ???
+
+  override def changeObjectStorageClass(bucketName: String, key: String, newStorageClass: StorageClass): Unit = ???
+
+  override def setObjectRedirectLocation(bucketName: String, key: String, newRedirectLocation: String): Unit = ???
+
+  override def listObjects(bucketName: String): ObjectListing = ???
+
+  override def listObjects(bucketName: String, prefix: String): ObjectListing = ???
+
+  override def listObjects(listObjectsRequest: ListObjectsRequest): ObjectListing = ???
+
+  override def listObjectsV2(bucketName: String): ListObjectsV2Result = ???
+
+  override def listObjectsV2(bucketName: String, prefix: String): ListObjectsV2Result = ???
+
+  override def listObjectsV2(listObjectsV2Request: ListObjectsV2Request): ListObjectsV2Result = ???
+
+  override def listNextBatchOfObjects(previousObjectListing: ObjectListing): ObjectListing = ???
+
+  override def listNextBatchOfObjects(listNextBatchOfObjectsRequest: ListNextBatchOfObjectsRequest): ObjectListing = ???
+
+  override def listVersions(bucketName: String, prefix: String): VersionListing = ???
+
+  override def listNextBatchOfVersions(previousVersionListing: VersionListing): VersionListing = ???
+
+  override def listNextBatchOfVersions(listNextBatchOfVersionsRequest: ListNextBatchOfVersionsRequest): VersionListing = ???
+
+  override def listVersions(bucketName: String, prefix: String, keyMarker: String, versionIdMarker: String, delimiter: String, maxResults: Integer): VersionListing = ???
+
+  override def listVersions(listVersionsRequest: ListVersionsRequest): VersionListing = ???
+
+  override def getS3AccountOwner: Owner = ???
+
+  override def getS3AccountOwner(getS3AccountOwnerRequest: GetS3AccountOwnerRequest): Owner = ???
+
+  override def doesBucketExist(bucketName: String): Boolean = ???
+
+  override def doesBucketExistV2(bucketName: String): Boolean = ???
+
+  override def headBucket(headBucketRequest: HeadBucketRequest): HeadBucketResult = ???
+
+  override def listBuckets(): util.List[Bucket] = ???
+
+  override def listBuckets(listBucketsRequest: ListBucketsRequest): util.List[Bucket] = ???
+
+  override def getBucketLocation(bucketName: String): String = ???
+
+  override def getBucketLocation(getBucketLocationRequest: GetBucketLocationRequest): String = ???
+
+  override def createBucket(createBucketRequest: CreateBucketRequest): Bucket = ???
+
+  override def createBucket(bucketName: String): Bucket = ???
+
+  override def createBucket(bucketName: String, region: model.Region): Bucket = ???
+
+  override def createBucket(bucketName: String, region: String): Bucket = ???
+
+  override def getObjectAcl(bucketName: String, key: String): AccessControlList = ???
+
+  override def getObjectAcl(bucketName: String, key: String, versionId: String): AccessControlList = ???
+
+  override def getObjectAcl(getObjectAclRequest: GetObjectAclRequest): AccessControlList = ???
+
+  override def setObjectAcl(bucketName: String, key: String, acl: AccessControlList): Unit = ???
+
+  override def setObjectAcl(bucketName: String, key: String, acl: CannedAccessControlList): Unit = ???
+
+  override def setObjectAcl(bucketName: String, key: String, versionId: String, acl: AccessControlList): Unit = ???
+
+  override def setObjectAcl(bucketName: String, key: String, versionId: String, acl: CannedAccessControlList): Unit = ???
+
+  override def setObjectAcl(setObjectAclRequest: SetObjectAclRequest): Unit = ???
+
+  override def getBucketAcl(bucketName: String): AccessControlList = ???
+
+  override def setBucketAcl(setBucketAclRequest: SetBucketAclRequest): Unit = ???
+
+  override def getBucketAcl(getBucketAclRequest: GetBucketAclRequest): AccessControlList = ???
+
+  override def setBucketAcl(bucketName: String, acl: AccessControlList): Unit = ???
+
+  override def setBucketAcl(bucketName: String, acl: CannedAccessControlList): Unit = ???
+
+  override def getObjectMetadata(bucketName: String, key: String): ObjectMetadata = ???
+
+  override def getObjectMetadata(getObjectMetadataRequest: GetObjectMetadataRequest): ObjectMetadata = ???
+
+  override def getObject(bucketName: String, key: String): S3Object = ???
+
+  override def getObject(getObjectRequest: GetObjectRequest): S3Object = ???
+
+  override def getObject(getObjectRequest: GetObjectRequest, destinationFile: File): ObjectMetadata = ???
+
+  override def getObjectAsString(bucketName: String, key: String): String = ???
+
+  override def getObjectTagging(getObjectTaggingRequest: GetObjectTaggingRequest): GetObjectTaggingResult = ???
+
+  override def setObjectTagging(setObjectTaggingRequest: SetObjectTaggingRequest): SetObjectTaggingResult = ???
+
+  override def deleteObjectTagging(deleteObjectTaggingRequest: DeleteObjectTaggingRequest): DeleteObjectTaggingResult = ???
+
+  override def deleteBucket(deleteBucketRequest: DeleteBucketRequest): Unit = ???
+
+  override def deleteBucket(bucketName: String): Unit = ???
+
+  override def putObject(putObjectRequest: PutObjectRequest): PutObjectResult = ???
+
+  override def putObject(bucketName: String, key: String, file: File): PutObjectResult = ???
+
+  override def putObject(bucketName: String, key: String, input: InputStream, metadata: ObjectMetadata): PutObjectResult = ???
+
+  override def putObject(bucketName: String, key: String, content: String): PutObjectResult = ???
+
+  override def copyObject(sourceBucketName: String, sourceKey: String, destinationBucketName: String, destinationKey: String): CopyObjectResult = ???
+
+  override def copyObject(copyObjectRequest: CopyObjectRequest): CopyObjectResult = ???
+
+  override def copyPart(copyPartRequest: CopyPartRequest): CopyPartResult = ???
+
+  override def deleteObject(bucketName: String, key: String): Unit = ???
+
+  override def deleteObject(deleteObjectRequest: DeleteObjectRequest): Unit = ???
+
+  override def deleteObjects(deleteObjectsRequest: DeleteObjectsRequest): DeleteObjectsResult = ???
+
+  override def deleteVersion(bucketName: String, key: String, versionId: String): Unit = ???
+
+  override def deleteVersion(deleteVersionRequest: DeleteVersionRequest): Unit = ???
+
+  override def getBucketLoggingConfiguration(bucketName: String): BucketLoggingConfiguration = ???
+
+  override def getBucketLoggingConfiguration(getBucketLoggingConfigurationRequest: GetBucketLoggingConfigurationRequest): BucketLoggingConfiguration = ???
+
+  override def setBucketLoggingConfiguration(setBucketLoggingConfigurationRequest: SetBucketLoggingConfigurationRequest): Unit = ???
+
+  override def getBucketVersioningConfiguration(bucketName: String): BucketVersioningConfiguration = ???
+
+  override def getBucketVersioningConfiguration(getBucketVersioningConfigurationRequest: GetBucketVersioningConfigurationRequest): BucketVersioningConfiguration = ???
+
+  override def setBucketVersioningConfiguration(setBucketVersioningConfigurationRequest: SetBucketVersioningConfigurationRequest): Unit = ???
+
+  override def getBucketLifecycleConfiguration(bucketName: String): BucketLifecycleConfiguration = ???
+
+  override def getBucketLifecycleConfiguration(getBucketLifecycleConfigurationRequest: GetBucketLifecycleConfigurationRequest): BucketLifecycleConfiguration = ???
+
+  override def setBucketLifecycleConfiguration(bucketName: String, bucketLifecycleConfiguration: BucketLifecycleConfiguration): Unit = ???
+
+  override def setBucketLifecycleConfiguration(setBucketLifecycleConfigurationRequest: SetBucketLifecycleConfigurationRequest): Unit = ???
+
+  override def deleteBucketLifecycleConfiguration(bucketName: String): Unit = ???
+
+  override def deleteBucketLifecycleConfiguration(deleteBucketLifecycleConfigurationRequest: DeleteBucketLifecycleConfigurationRequest): Unit = ???
+
+  override def getBucketCrossOriginConfiguration(bucketName: String): BucketCrossOriginConfiguration = ???
+
+  override def getBucketCrossOriginConfiguration(getBucketCrossOriginConfigurationRequest: GetBucketCrossOriginConfigurationRequest): BucketCrossOriginConfiguration = ???
+
+  override def setBucketCrossOriginConfiguration(bucketName: String, bucketCrossOriginConfiguration: BucketCrossOriginConfiguration): Unit = ???
+
+  override def setBucketCrossOriginConfiguration(setBucketCrossOriginConfigurationRequest: SetBucketCrossOriginConfigurationRequest): Unit = ???
+
+  override def deleteBucketCrossOriginConfiguration(bucketName: String): Unit = ???
+
+  override def deleteBucketCrossOriginConfiguration(deleteBucketCrossOriginConfigurationRequest: DeleteBucketCrossOriginConfigurationRequest): Unit = ???
+
+  override def getBucketTaggingConfiguration(bucketName: String): BucketTaggingConfiguration = ???
+
+  override def getBucketTaggingConfiguration(getBucketTaggingConfigurationRequest: GetBucketTaggingConfigurationRequest): BucketTaggingConfiguration = ???
+
+  override def setBucketTaggingConfiguration(bucketName: String, bucketTaggingConfiguration: BucketTaggingConfiguration): Unit = ???
+
+  override def setBucketTaggingConfiguration(setBucketTaggingConfigurationRequest: SetBucketTaggingConfigurationRequest): Unit = ???
+
+  override def deleteBucketTaggingConfiguration(bucketName: String): Unit = ???
+
+  override def deleteBucketTaggingConfiguration(deleteBucketTaggingConfigurationRequest: DeleteBucketTaggingConfigurationRequest): Unit = ???
+
+  override def getBucketNotificationConfiguration(bucketName: String): BucketNotificationConfiguration = ???
+
+  override def getBucketNotificationConfiguration(getBucketNotificationConfigurationRequest: GetBucketNotificationConfigurationRequest): BucketNotificationConfiguration = ???
+
+  override def setBucketNotificationConfiguration(setBucketNotificationConfigurationRequest: SetBucketNotificationConfigurationRequest): Unit = ???
+
+  override def setBucketNotificationConfiguration(bucketName: String, bucketNotificationConfiguration: BucketNotificationConfiguration): Unit = ???
+
+  override def getBucketWebsiteConfiguration(bucketName: String): BucketWebsiteConfiguration = ???
+
+  override def getBucketWebsiteConfiguration(getBucketWebsiteConfigurationRequest: GetBucketWebsiteConfigurationRequest): BucketWebsiteConfiguration = ???
+
+  override def setBucketWebsiteConfiguration(bucketName: String, configuration: BucketWebsiteConfiguration): Unit = ???
+
+  override def setBucketWebsiteConfiguration(setBucketWebsiteConfigurationRequest: SetBucketWebsiteConfigurationRequest): Unit = ???
+
+  override def deleteBucketWebsiteConfiguration(bucketName: String): Unit = ???
+
+  override def deleteBucketWebsiteConfiguration(deleteBucketWebsiteConfigurationRequest: DeleteBucketWebsiteConfigurationRequest): Unit = ???
+
+  override def getBucketPolicy(bucketName: String): BucketPolicy = ???
+
+  override def getBucketPolicy(getBucketPolicyRequest: GetBucketPolicyRequest): BucketPolicy = ???
+
+  override def setBucketPolicy(bucketName: String, policyText: String): Unit = ???
+
+  override def setBucketPolicy(setBucketPolicyRequest: SetBucketPolicyRequest): Unit = ???
+
+  override def deleteBucketPolicy(bucketName: String): Unit = ???
+
+  override def deleteBucketPolicy(deleteBucketPolicyRequest: DeleteBucketPolicyRequest): Unit = ???
+
+  override def generatePresignedUrl(bucketName: String, key: String, expiration: Date): URL = ???
+
+  override def generatePresignedUrl(bucketName: String, key: String, expiration: Date, method: HttpMethod): URL = ???
+
+  override def generatePresignedUrl(generatePresignedUrlRequest: GeneratePresignedUrlRequest): URL = ???
+
+  override def initiateMultipartUpload(request: InitiateMultipartUploadRequest): InitiateMultipartUploadResult = ???
+
+  override def uploadPart(request: UploadPartRequest): UploadPartResult = ???
+
+  override def listParts(request: ListPartsRequest): PartListing = ???
+
+  override def abortMultipartUpload(request: AbortMultipartUploadRequest): Unit = ???
+
+  override def completeMultipartUpload(request: CompleteMultipartUploadRequest): CompleteMultipartUploadResult = ???
+
+  override def listMultipartUploads(request: ListMultipartUploadsRequest): MultipartUploadListing = ???
+
+  override def getCachedResponseMetadata(request: AmazonWebServiceRequest): S3ResponseMetadata = ???
+
+  override def restoreObject(request: RestoreObjectRequest): Unit = ???
+
+  override def restoreObjectV2(request: RestoreObjectRequest): RestoreObjectResult = ???
+
+  override def restoreObject(bucketName: String, key: String, expirationInDays: Int): Unit = ???
+
+  override def enableRequesterPays(bucketName: String): Unit = ???
+
+  override def disableRequesterPays(bucketName: String): Unit = ???
+
+  override def isRequesterPaysEnabled(bucketName: String): Boolean = ???
+
+  override def setBucketReplicationConfiguration(bucketName: String, configuration: BucketReplicationConfiguration): Unit = ???
+
+  override def setBucketReplicationConfiguration(setBucketReplicationConfigurationRequest: SetBucketReplicationConfigurationRequest): Unit = ???
+
+  override def getBucketReplicationConfiguration(bucketName: String): BucketReplicationConfiguration = ???
+
+  override def getBucketReplicationConfiguration(getBucketReplicationConfigurationRequest: GetBucketReplicationConfigurationRequest): BucketReplicationConfiguration = ???
+
+  override def deleteBucketReplicationConfiguration(bucketName: String): Unit = ???
+
+  override def deleteBucketReplicationConfiguration(request: DeleteBucketReplicationConfigurationRequest): Unit = ???
+
+  override def doesObjectExist(bucketName: String, objectName: String): Boolean = ???
+
+  override def getBucketAccelerateConfiguration(bucketName: String): BucketAccelerateConfiguration = ???
+
+  override def getBucketAccelerateConfiguration(getBucketAccelerateConfigurationRequest: GetBucketAccelerateConfigurationRequest): BucketAccelerateConfiguration = ???
+
+  override def setBucketAccelerateConfiguration(bucketName: String, accelerateConfiguration: BucketAccelerateConfiguration): Unit = ???
+
+  override def setBucketAccelerateConfiguration(setBucketAccelerateConfigurationRequest: SetBucketAccelerateConfigurationRequest): Unit = ???
+
+  override def deleteBucketMetricsConfiguration(bucketName: String, id: String): DeleteBucketMetricsConfigurationResult = ???
+
+  override def deleteBucketMetricsConfiguration(deleteBucketMetricsConfigurationRequest: DeleteBucketMetricsConfigurationRequest): DeleteBucketMetricsConfigurationResult = ???
+
+  override def getBucketMetricsConfiguration(bucketName: String, id: String): GetBucketMetricsConfigurationResult = ???
+
+  override def getBucketMetricsConfiguration(getBucketMetricsConfigurationRequest: GetBucketMetricsConfigurationRequest): GetBucketMetricsConfigurationResult = ???
+
+  override def setBucketMetricsConfiguration(bucketName: String, metricsConfiguration: MetricsConfiguration): SetBucketMetricsConfigurationResult = ???
+
+  override def setBucketMetricsConfiguration(setBucketMetricsConfigurationRequest: SetBucketMetricsConfigurationRequest): SetBucketMetricsConfigurationResult = ???
+
+  override def listBucketMetricsConfigurations(listBucketMetricsConfigurationsRequest: ListBucketMetricsConfigurationsRequest): ListBucketMetricsConfigurationsResult = ???
+
+  override def deleteBucketAnalyticsConfiguration(bucketName: String, id: String): DeleteBucketAnalyticsConfigurationResult = ???
+
+  override def deleteBucketAnalyticsConfiguration(deleteBucketAnalyticsConfigurationRequest: DeleteBucketAnalyticsConfigurationRequest): DeleteBucketAnalyticsConfigurationResult = ???
+
+  override def getBucketAnalyticsConfiguration(bucketName: String, id: String): GetBucketAnalyticsConfigurationResult = ???
+
+  override def getBucketAnalyticsConfiguration(getBucketAnalyticsConfigurationRequest: GetBucketAnalyticsConfigurationRequest): GetBucketAnalyticsConfigurationResult = ???
+
+  override def setBucketAnalyticsConfiguration(bucketName: String, analyticsConfiguration: AnalyticsConfiguration): SetBucketAnalyticsConfigurationResult = ???
+
+  override def setBucketAnalyticsConfiguration(setBucketAnalyticsConfigurationRequest: SetBucketAnalyticsConfigurationRequest): SetBucketAnalyticsConfigurationResult = ???
+
+  override def listBucketAnalyticsConfigurations(listBucketAnalyticsConfigurationsRequest: ListBucketAnalyticsConfigurationsRequest): ListBucketAnalyticsConfigurationsResult = ???
+
+  override def deleteBucketInventoryConfiguration(bucketName: String, id: String): DeleteBucketInventoryConfigurationResult = ???
+
+  override def deleteBucketInventoryConfiguration(deleteBucketInventoryConfigurationRequest: DeleteBucketInventoryConfigurationRequest): DeleteBucketInventoryConfigurationResult = ???
+
+  override def getBucketInventoryConfiguration(bucketName: String, id: String): GetBucketInventoryConfigurationResult = ???
+
+  override def getBucketInventoryConfiguration(getBucketInventoryConfigurationRequest: GetBucketInventoryConfigurationRequest): GetBucketInventoryConfigurationResult = ???
+
+  override def setBucketInventoryConfiguration(bucketName: String, inventoryConfiguration: InventoryConfiguration): SetBucketInventoryConfigurationResult = ???
+
+  override def setBucketInventoryConfiguration(setBucketInventoryConfigurationRequest: SetBucketInventoryConfigurationRequest): SetBucketInventoryConfigurationResult = ???
+
+  override def listBucketInventoryConfigurations(listBucketInventoryConfigurationsRequest: ListBucketInventoryConfigurationsRequest): ListBucketInventoryConfigurationsResult = ???
+
+  override def deleteBucketEncryption(bucketName: String): DeleteBucketEncryptionResult = ???
+
+  override def deleteBucketEncryption(request: DeleteBucketEncryptionRequest): DeleteBucketEncryptionResult = ???
+
+  override def getBucketEncryption(bucketName: String): GetBucketEncryptionResult = ???
+
+  override def getBucketEncryption(request: GetBucketEncryptionRequest): GetBucketEncryptionResult = ???
+
+  override def setBucketEncryption(setBucketEncryptionRequest: SetBucketEncryptionRequest): SetBucketEncryptionResult = ???
+
+  override def setPublicAccessBlock(request: SetPublicAccessBlockRequest): SetPublicAccessBlockResult = ???
+
+  override def getPublicAccessBlock(request: GetPublicAccessBlockRequest): GetPublicAccessBlockResult = ???
+
+  override def deletePublicAccessBlock(request: DeletePublicAccessBlockRequest): DeletePublicAccessBlockResult = ???
+
+  override def getBucketPolicyStatus(request: GetBucketPolicyStatusRequest): GetBucketPolicyStatusResult = ???
+
+  override def selectObjectContent(selectRequest: SelectObjectContentRequest): SelectObjectContentResult = ???
+
+  override def setObjectLegalHold(setObjectLegalHoldRequest: SetObjectLegalHoldRequest): SetObjectLegalHoldResult = ???
+
+  override def getObjectLegalHold(getObjectLegalHoldRequest: GetObjectLegalHoldRequest): GetObjectLegalHoldResult = ???
+
+  override def setObjectLockConfiguration(setObjectLockConfigurationRequest: SetObjectLockConfigurationRequest): SetObjectLockConfigurationResult = ???
+
+  override def getObjectLockConfiguration(getObjectLockConfigurationRequest: GetObjectLockConfigurationRequest): GetObjectLockConfigurationResult = ???
+
+  override def setObjectRetention(setObjectRetentionRequest: SetObjectRetentionRequest): SetObjectRetentionResult = ???
+
+  override def getObjectRetention(getObjectRetentionRequest: GetObjectRetentionRequest): GetObjectRetentionResult = ???
+
+  override def download(presignedUrlDownloadRequest: PresignedUrlDownloadRequest): PresignedUrlDownloadResult = ???
+
+  override def download(presignedUrlDownloadRequest: PresignedUrlDownloadRequest, destinationFile: File): Unit = ???
+
+  override def upload(presignedUrlUploadRequest: PresignedUrlUploadRequest): PresignedUrlUploadResult = ???
+
+  override def shutdown(): Unit = ???
+
+  override def getRegion: model.Region = ???
+
+  override def getRegionName: String = ???
+
+  override def getUrl(bucketName: String, key: String): URL = ???
+
+  override def waiters(): AmazonS3Waiters = ???
+}
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/MyS3CatsIOClient.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/MyS3CatsIOClient.scala
new file mode 100644
index 0000000..d478fad
--- /dev/null
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/MyS3CatsIOClient.scala
@@ -0,0 +1,15 @@
+package net.kemitix.s3thorp.awssdk
+
+import com.github.j5ik2o.reactive.aws.s3.S3AsyncClient
+import com.github.j5ik2o.reactive.aws.s3.cats.S3CatsIOClient
+import software.amazon.awssdk.services.s3
+
+trait MyS3CatsIOClient extends S3CatsIOClient {
+  override val underlying: S3AsyncClient = new S3AsyncClient {
+    override val underlying: s3.S3AsyncClient = new s3.S3AsyncClient {
+      override def serviceName(): String = "fake-s3-client"
+
+      override def close(): Unit = ()
+    }
+  }
+}
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManagerSuite.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManagerSuite.scala
new file mode 100644
index 0000000..db904c8
--- /dev/null
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartTransferManagerSuite.scala
@@ -0,0 +1,112 @@
+package net.kemitix.s3thorp.awssdk
+
+import java.io.File
+import java.time.Instant
+
+import com.amazonaws.AmazonClientException
+import com.amazonaws.services.s3.model
+import com.amazonaws.services.s3.transfer.model.UploadResult
+import com.amazonaws.services.s3.transfer.{PauseResult, PersistableUpload, Transfer, TransferManager, TransferProgress, Upload}
+import net.kemitix.s3thorp.{Bucket, Config, KeyGenerator, LastModified, MD5Hash, MD5HashGenerator, RemoteKey, Resource, UnitTest, UploadS3Action}
+
+class S3ClientMultiPartTransferManagerSuite
+  extends UnitTest
+    with KeyGenerator {
+
+  private val source = Resource(this, "..")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val fileToKey = generateKey(config.source, config.prefix) _
+  val lastModified = LastModified(Instant.now())
+
+  describe("S3ClientMultiPartTransferManagerSuite") {
+    describe("accepts") {
+      val transferManager = new MyTransferManager(("", "", new File("")), RemoteKey(""), MD5Hash(""))
+      val uploader = new S3ClientMultiPartTransferManager(transferManager)
+      describe("small-file") {
+        val smallFile = aLocalFile("small-file", MD5Hash("the-hash"), source, fileToKey)
+        it("should be a small-file") {
+          assert(smallFile.file.length < 5 * 1024 * 1024)
+        }
+        it("should not accept small-file") {
+          assertResult(false)(uploader.accepts(smallFile))
+        }
+      }
+      describe("big-file") {
+        val bigFile = aLocalFile("big-file", MD5Hash("the-hash"), source, fileToKey)
+        it("should be a big-file") {
+          assert(bigFile.file.length > 5 * 1024 * 1024)
+        }
+        it("should accept big-file") {
+          assertResult(true)(uploader.accepts(bigFile))
+        }
+      }
+    }
+    describe("upload") {
+      val returnedKey = RemoteKey("returned-key")
+      val returnedHash = MD5Hash("returned-hash")
+      val bigFile = aLocalFile("small-file", MD5Hash("the-hash"), source, fileToKey)
+      val transferManager = new MyTransferManager(
+        (config.bucket.name, bigFile.remoteKey.key, bigFile.file),
+        returnedKey, returnedHash)
+      val uploader = new S3ClientMultiPartTransferManager(transferManager)
+      it("should upload") {
+        val expected = UploadS3Action(returnedKey, returnedHash)
+        val result = uploader.upload(bigFile, config.bucket, 1).unsafeRunSync
+        assertResult(expected)(result)
+      }
+    }
+  }
+
+  class MyTransferManager(signature: (String, String, File),
+                          returnedKey: RemoteKey,
+                          returnedHash: MD5Hash) extends TransferManager {
+    override def upload(bucketName: String, key: String, file: File): Upload = {
+      if ((bucketName, key, file) == signature) {
+        new MyUpload {
+          override def waitForUploadResult(): UploadResult = {
+            val result = new UploadResult()
+            result.setBucketName(bucketName)
+            result.setETag(returnedHash.hash)
+            result.setKey(returnedKey.key)
+            result.setVersionId("version-id")
+            result
+          }
+        }
+      } else new MyUpload
+    }
+  }
+  class MyUpload extends Upload {
+
+    override def waitForUploadResult(): UploadResult = ???
+
+    override def pause(): PersistableUpload = ???
+
+    override def tryPause(forceCancelTransfers: Boolean): PauseResult[PersistableUpload] = ???
+
+    override def abort(): Unit = ???
+
+    override def isDone: Boolean = ???
+
+    override def waitForCompletion(): Unit = ???
+
+    override def waitForException(): AmazonClientException = ???
+
+    override def getDescription: String = ???
+
+    override def getState: Transfer.TransferState = ???
+
+    override def getProgress: TransferProgress = ???
+
+    import com.amazonaws.event.ProgressListener
+
+    override def addProgressListener(listener: ProgressListener): Unit = ???
+
+    override def removeProgressListener(listener: ProgressListener): Unit = ???
+
+    override def addProgressListener(listener: model.ProgressListener): Unit = ???
+
+    override def removeProgressListener(listener: model.ProgressListener): Unit = ???
+  }
+
+}
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderSuite.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderSuite.scala
new file mode 100644
index 0000000..2f30b91
--- /dev/null
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientMultiPartUploaderSuite.scala
@@ -0,0 +1,279 @@
+package net.kemitix.s3thorp.awssdk
+
+import scala.collection.JavaConverters._
+import java.util.concurrent.atomic.{AtomicBoolean, AtomicInteger, AtomicReference}
+
+import com.amazonaws.services.s3.model.{Bucket => _, _}
+import net.kemitix.s3thorp._
+
+class S3ClientMultiPartUploaderSuite
+  extends UnitTest
+    with KeyGenerator {
+
+  private val source = Resource(this, "..")
+  private val prefix = RemoteKey("prefix")
+  implicit private val config: Config = Config(Bucket("bucket"), prefix, source = source)
+  private val fileToKey = generateKey(config.source, config.prefix) _
+
+  describe("multi-part uploader accepts") {
+    val uploader = new S3ClientMultiPartUploader(new MyAmazonS3Client {})
+
+    it("should reject small file") {
+      // small-file: dd if=/dev/urandom of=src/test/resources/net/kemitix/s3thorp/small-file bs=1047552 count=5
+      // 1047552 = 1024 * 1023
+      // file size 5kb under 5Mb threshold
+      val smallFile = aLocalFile("small-file", MD5Hash(""), source, fileToKey)
+      assert(smallFile.file.exists, "sample small file is missing")
+      assert(smallFile.file.length == 5 * 1024 * 1023, "sample small file is wrong size")
+      val result = uploader.accepts(smallFile)
+      assertResult(false)(result)
+    }
+    it("should accept big file") {
+      // big-file: dd if=/dev/urandom of=src/test/resources/net/kemitix/s3thorp/big-file bs=1049600 count=5
+      // 1049600 = 1024 * 1025
+      // file size 5kb over 5Mb threshold
+      val bigFile = aLocalFile("big-file", MD5Hash(""), source, fileToKey)
+      assert(bigFile.file.exists, "sample big file is missing")
+      assert(bigFile.file.length == 5 * 1024 * 1025, "sample big file is wrong size")
+      val result = uploader.accepts(bigFile)
+      assertResult(true)(result)
+    }
+  }
+
+  def uploadPartRequest(partNumber: Int) = {
+    val request = new UploadPartRequest
+    request.setPartNumber(partNumber)
+    request
+  }
+
+  def uploadPartResult(eTag: String) = {
+    val result = new UploadPartResult
+    result.setETag(eTag)
+    result
+  }
+
+  describe("mulit-part uploader upload") {
+    val theFile = aLocalFile("big-file", MD5Hash(""), source, fileToKey)
+    val uploadId = "upload-id"
+    val createUploadResponse = new InitiateMultipartUploadResult()
+    createUploadResponse.setBucketName(config.bucket.name)
+    createUploadResponse.setKey(theFile.remoteKey.key)
+    createUploadResponse.setUploadId(uploadId)
+    val uploadPartRequest1 = uploadPartRequest(1)
+    val uploadPartRequest2 = uploadPartRequest(2)
+    val uploadPartRequest3 = uploadPartRequest(3)
+    val part1md5 = "aadf0d266cefe0fcdb241a51798d74b3"
+    val part2md5 = "16e08d53ca36e729d808fd5e4f7e35dc"
+    val uploadPartResponse1 = uploadPartResult(part1md5)
+    val uploadPartResponse2 = uploadPartResult(part2md5)
+    val uploadPartResponse3 = uploadPartResult("part-3")
+    val completeUploadResponse = new CompleteMultipartUploadResult()
+    completeUploadResponse.setETag("hash")
+    describe("multi-part uploader upload components") {
+      val uploader = new RecordingMultiPartUploader()
+      describe("create upload request") {
+        val request = uploader.createUploadRequest(config.bucket, theFile)
+        it("should have bucket") {
+          assertResult(config.bucket.name)(request.getBucketName)
+        }
+        it("should have key") {
+          assertResult(theFile.remoteKey.key)(request.getKey)
+        }
+      }
+      describe("initiate upload") {
+        it("should createMultipartUpload") {
+          val expected = createUploadResponse
+          val result = uploader.createUpload(config.bucket, theFile).unsafeRunSync
+          assertResult(expected)(result)
+        }
+      }
+      describe("create UploadPartRequests for file") {
+        val chunkSize = 5l * 1024 * 1025 / 2
+        // to create expected md5 values for each chunk:
+        // split -d -b $((5 * 1024 * 1025 / 2)) big-file
+        // creates x00 and x01
+        // md5sum x0[01]
+        val result = uploader.parts(theFile, createUploadResponse).unsafeRunSync.toList
+        it("should create two parts") {
+          assertResult(2)(result.size)
+        }
+        it("create part 1") {
+          val part1 = result(0)
+          assertResult((1, chunkSize, part1md5))((part1.getPartNumber, part1.getPartSize, part1.getMd5Digest))
+        }
+        it("create part 2") {
+          val part2 = result(1)
+          assertResult((2, chunkSize, part2md5))((part2.getPartNumber, part2.getPartSize, part2.getMd5Digest))
+        }
+      }
+      describe("upload part") {
+        it("should uploadPart") {
+          val expected = uploadPartResponse3
+          val result = uploader.uploadPart(theFile)(config)(uploadPartRequest3).unsafeRunSync
+          assertResult(expected)(result)
+        }
+      }
+      describe("upload parts") {
+        val uploadPartRequests = Stream(uploadPartRequest1, uploadPartRequest2)
+        it("should uploadPart for each") {
+          val expected = List(uploadPartResponse1, uploadPartResponse2)
+          val result = uploader.uploadParts(theFile, uploadPartRequests).unsafeRunSync.toList
+          assertResult(expected)(result)
+        }
+      }
+      describe("create complete request") {
+        val request = uploader.createCompleteRequest(createUploadResponse, List(uploadPartResponse1, uploadPartResponse2))
+        it("should have the bucket name") {
+          assertResult(config.bucket.name)(request.getBucketName)
+        }
+        it("should have the key") {
+          assertResult(theFile.remoteKey.key)(request.getKey)
+        }
+        it("should have the upload id") {
+          assertResult(uploadId)(request.getUploadId)
+        }
+        it("should have the etags") {
+          val expected = List(new PartETag(1, part1md5), new PartETag(2, part2md5))
+          assertResult(expected.map(_.getETag))(request.getPartETags.asScala.map(_.getETag))
+        }
+      }
+      describe("complete upload") {
+        val uploadPartResponses = Stream(uploadPartResponse1, uploadPartResponse2, uploadPartResponse3)
+        it("should completeUpload") {
+          val expected = completeUploadResponse
+          val result = uploader.completeUpload(createUploadResponse, uploadPartResponses, theFile).unsafeRunSync
+          assertResult(expected)(result)
+        }
+      }
+      describe("create abort request") {
+        val abortRequest = uploader.createAbortRequest(uploadId, theFile)
+        it("should have the upload id") {
+          assertResult(uploadId)(abortRequest.getUploadId)
+        }
+        it("should have the bucket") {
+          assertResult(config.bucket.name)(abortRequest.getBucketName)
+        }
+        it("should have the key") {
+          assertResult(theFile.remoteKey.key)(abortRequest.getKey)
+        }
+      }
+      describe("abort upload") {
+        it("should abortUpload") {
+          pending
+        }
+      }
+    }
+    describe("multi-part uploader upload complete") {
+      describe("upload") {
+        describe("when all okay") {
+          val uploader = new RecordingMultiPartUploader()
+          uploader.upload(theFile, config.bucket, 1).unsafeRunSync
+          it("should initiate the upload") {
+            assert(uploader.initiated.get)
+          }
+          it("should upload both parts") {
+            assertResult(Set(1, 2))(uploader.partsUploaded.get)
+          }
+          it("should complete the upload") {
+            assert(uploader.completed.get)
+          }
+        }
+        describe("when initiate upload fails") {
+          val uploader = new RecordingMultiPartUploader(initOkay = false)
+          uploader.upload(theFile, config.bucket, 1).unsafeRunSync
+          it("should not upload any parts") {
+            assertResult(Set())(uploader.partsUploaded.get)
+          }
+          it("should not complete the upload") {
+            assertResult(false)(uploader.completed.get)
+          }
+        }
+        describe("when uploading a part fails once") {
+          val uploader = new RecordingMultiPartUploader(partTriesRequired = 2)
+          uploader.upload(theFile, config.bucket, 1).unsafeRunSync
+          it("should initiate the upload") {
+            assert(uploader.initiated.get)
+          }
+          it("should upload all parts") {
+            assertResult(Set(1, 2))(uploader.partsUploaded.get)
+          }
+          it("should complete the upload") {
+            assert(uploader.completed.get)
+          }
+        }
+        describe("when uploading a part fails too many times") {
+          val uploader = new RecordingMultiPartUploader(partTriesRequired = 4)
+          uploader.upload(theFile, config.bucket, 1).unsafeRunSync
+          it("should initiate the upload") {
+            assert(uploader.initiated.get)
+          }
+          it("should not complete the upload") {
+            assertResult(Set())(uploader.partsUploaded.get)
+          }
+          it("should cancel the upload") {
+            assert(uploader.canceled.get)
+          }
+        }
+      }
+    }
+    class RecordingMultiPartUploader(initOkay: Boolean = true,
+                                     partTriesRequired: Int = 1,
+                                     val initiated: AtomicBoolean = new AtomicBoolean(false),
+                                     val partsUploaded: AtomicReference[Set[Int]] = new AtomicReference[Set[Int]](Set()),
+                                     val part0Tries: AtomicInteger = new AtomicInteger(0),
+                                     val part1Tries: AtomicInteger = new AtomicInteger(0),
+                                     val part2Tries: AtomicInteger = new AtomicInteger(0),
+                                     val completed: AtomicBoolean = new AtomicBoolean(false),
+                                     val canceled: AtomicBoolean = new AtomicBoolean(false))
+      extends S3ClientMultiPartUploader(
+        new MyAmazonS3Client {
+
+          def error[A]: A = {
+            val exception = new AmazonS3Exception("error")
+            exception.setAdditionalDetails(Map("Content-MD5" -> "(hash)").asJava)
+            throw exception
+          }
+
+          override def initiateMultipartUpload(createMultipartUploadRequest: InitiateMultipartUploadRequest): InitiateMultipartUploadResult =
+            if (initOkay) {
+              initiated set true
+              createUploadResponse
+            }
+            else error
+
+          override def uploadPart(uploadPartRequest: UploadPartRequest): UploadPartResult =
+            uploadPartRequest match {
+              case _ if uploadPartRequest.getPartNumber == 1 => {
+                if (part0Tries.incrementAndGet >= partTriesRequired) {
+                  partsUploaded getAndUpdate (t => t + 1)
+                  uploadPartResponse1
+                }
+                else error
+              }
+              case _ if uploadPartRequest.getPartNumber == 2 => {
+                if (part1Tries.incrementAndGet >= partTriesRequired) {
+                  partsUploaded getAndUpdate (t => t + 2)
+                  uploadPartResponse2
+                }
+                else error
+              }
+              case _ if uploadPartRequest.getPartNumber == 3 => {
+                if (part2Tries.incrementAndGet >= partTriesRequired) {
+                  partsUploaded getAndUpdate (t => t + 3)
+                  uploadPartResponse3
+                }
+                else error
+              }
+            }
+
+          override def completeMultipartUpload(completeMultipartUploadRequest: CompleteMultipartUploadRequest): CompleteMultipartUploadResult = {
+            completed set true
+            completeUploadResponse
+          }
+
+          override def abortMultipartUpload(abortMultipartUploadRequest: AbortMultipartUploadRequest): Unit = {
+            canceled set true
+          }
+        }) {}
+  }
+}
\ No newline at end of file
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientSuite.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientSuite.scala
index de38611..5dc87d0 100644
--- a/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientSuite.scala
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/S3ClientSuite.scala
@@ -76,7 +76,7 @@ class S3ClientSuite
 
   describe("upload") {
     def invoke(s3Client: ThorpS3Client, localFile: LocalFile, bucket: Bucket) =
-      s3Client.upload(localFile, bucket).unsafeRunSync
+      s3Client.upload(localFile, bucket, 1).unsafeRunSync
     describe("when uploading a file") {
       val md5Hash = MD5Hash("the-md5hash")
       val s3Client = new ThorpS3Client(
diff --git a/src/test/scala/net/kemitix/s3thorp/awssdk/ThorpS3ClientSuite.scala b/src/test/scala/net/kemitix/s3thorp/awssdk/ThorpS3ClientSuite.scala
index c2b3016..dd7db30 100644
--- a/src/test/scala/net/kemitix/s3thorp/awssdk/ThorpS3ClientSuite.scala
+++ b/src/test/scala/net/kemitix/s3thorp/awssdk/ThorpS3ClientSuite.scala
@@ -57,13 +57,5 @@ class ThorpS3ClientSuite extends FunSpec {
       assertResult(expected)(result)
     }
   }
-  trait MyS3CatsIOClient extends S3CatsIOClient {
-    override val underlying: S3AsyncClient = new S3AsyncClient {
-      override val underlying: s3.S3AsyncClient = new s3.S3AsyncClient {
-        override def serviceName(): String = "fake-s3-client"
 
-        override def close(): Unit = ()
-      }
-    }
-  }
 }