diff --git a/src/main/java/net/kemitix/gitdb/GitDBLocal.java b/src/main/java/net/kemitix/gitdb/GitDBLocal.java
index 5f6954c..148e5fd 100644
--- a/src/main/java/net/kemitix/gitdb/GitDBLocal.java
+++ b/src/main/java/net/kemitix/gitdb/GitDBLocal.java
@@ -53,7 +53,7 @@ class GitDBLocal implements GitDB {
 
     @Override
     public <T> T save(Branch branch, Message message, Document<T> document, Author author) {
-        return null;
+        return document.getValue();
     }
 
     @Override
diff --git a/src/test/java/net/kemitix/gitdb/GitDBTest.java b/src/test/java/net/kemitix/gitdb/GitDBTest.java
index c9b4034..92cc2d8 100644
--- a/src/test/java/net/kemitix/gitdb/GitDBTest.java
+++ b/src/test/java/net/kemitix/gitdb/GitDBTest.java
@@ -10,6 +10,7 @@ import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Comparator;
+import java.util.UUID;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -17,6 +18,10 @@ class GitDBTest {
 
     private final Path dbDir = Files.createTempDirectory("gitdb");
     private final GitDB gitDB = GitDB.local(dbDir);
+    private final Branch master = Branch.name("master");
+    private final Message message = Message.message(UUID.randomUUID().toString());
+    private final Key key = Key.name(UUID.randomUUID().toString());
+    private final Author author = Author.name("junit");
 
     GitDBTest() throws IOException, GitAPIException {
     }
@@ -33,7 +38,16 @@ class GitDBTest {
         assertThat(repository.getRefDatabase()).isNotNull();
     }
 
-
+    @Test
+    void saveDocumentGivesSavedValue() {
+        //given
+        final String value = UUID.randomUUID().toString();
+        final Document<String> document = Document.create(key, value);
+        //when
+        final String result = gitDB.save(master, message, document, author);
+        //then
+        assertThat(result).isEqualTo(value);
+    }
 
     @AfterEach
     void tearDown() throws IOException {