From 11575f53e78f7d1715b2654d9e0cadc20d5cd583 Mon Sep 17 00:00:00 2001
From: Paul Campbell <pcampbell@kemitix.net>
Date: Sat, 2 Jun 2018 12:35:14 +0100
Subject: [PATCH] When select a branch that doesn't exist then an empty
 Optional is returned

---
 src/main/java/net/kemitix/gitdb/GitDB.java    |  9 ++++++++
 .../gitdb/{Branch.java => GitDBBranch.java}   | 18 +++++++---------
 .../java/net/kemitix/gitdb/GitDBLocal.java    |  6 ++++++
 .../java/net/kemitix/gitdb/GitDBTest.java     | 21 ++++++++++++++++---
 4 files changed, 40 insertions(+), 14 deletions(-)
 rename src/main/java/net/kemitix/gitdb/{Branch.java => GitDBBranch.java} (81%)

diff --git a/src/main/java/net/kemitix/gitdb/GitDB.java b/src/main/java/net/kemitix/gitdb/GitDB.java
index 296e2d5..fc4f292 100644
--- a/src/main/java/net/kemitix/gitdb/GitDB.java
+++ b/src/main/java/net/kemitix/gitdb/GitDB.java
@@ -26,6 +26,7 @@ import org.eclipse.jgit.errors.RepositoryNotFoundException;
 
 import java.io.IOException;
 import java.nio.file.Path;
+import java.util.Optional;
 
 /**
  * Main API for connecting to a Git repo as a database.
@@ -63,4 +64,12 @@ public interface GitDB {
             throw new GitDBRepoNotFoundException(dbDir, e);
         }
     }
+
+    /**
+     * Select the named branch.
+     *
+     * @param name the branch to select
+     * @return an Optional containing the branch if it exists
+     */
+    Optional<GitDBBranch> branch(String name);
 }
diff --git a/src/main/java/net/kemitix/gitdb/Branch.java b/src/main/java/net/kemitix/gitdb/GitDBBranch.java
similarity index 81%
rename from src/main/java/net/kemitix/gitdb/Branch.java
rename to src/main/java/net/kemitix/gitdb/GitDBBranch.java
index 788aba5..3223947 100644
--- a/src/main/java/net/kemitix/gitdb/Branch.java
+++ b/src/main/java/net/kemitix/gitdb/GitDBBranch.java
@@ -21,14 +21,10 @@
 
 package net.kemitix.gitdb;
 
-//import net.kemitix.mon.TypeAlias;
-
-//public class Branch extends TypeAlias<String> {
-//    protected Branch(final String value) {
-//        super(value);
-//    }
-//
-//    static Branch name(final String name) {
-//        return new Branch(name);
-//    }
-//}
+/**
+ * API for interacting with a branch in a GirDB.
+ *
+ * @author Paul Campbell (pcampbell@kemitix.net)
+ */
+public interface GitDBBranch {
+}
diff --git a/src/main/java/net/kemitix/gitdb/GitDBLocal.java b/src/main/java/net/kemitix/gitdb/GitDBLocal.java
index f0e1faa..8c8f92e 100644
--- a/src/main/java/net/kemitix/gitdb/GitDBLocal.java
+++ b/src/main/java/net/kemitix/gitdb/GitDBLocal.java
@@ -31,6 +31,7 @@ import java.io.IOException;
 import java.nio.file.DirectoryNotEmptyException;
 import java.nio.file.Files;
 import java.nio.file.NotDirectoryException;
+import java.util.Optional;
 
 /**
  * Implementation of GitDB for working with a local Repo.
@@ -99,6 +100,11 @@ class GitDBLocal implements GitDB {
         return initCommand.setGitDir(dbDir).setBare(true).call();
     }
 
+    @Override
+    public Optional<GitDBBranch> branch(final String name) {
+        return Optional.empty();
+    }
+
     //    @Override
     //    @SneakyThrows
     //    public <T> T get(Branch branch, Key key, Class<T> type) {
diff --git a/src/test/java/net/kemitix/gitdb/GitDBTest.java b/src/test/java/net/kemitix/gitdb/GitDBTest.java
index 679074c..4018182 100644
--- a/src/test/java/net/kemitix/gitdb/GitDBTest.java
+++ b/src/test/java/net/kemitix/gitdb/GitDBTest.java
@@ -11,6 +11,7 @@ import org.mockito.junit.jupiter.MockitoExtension;
 import java.io.IOException;
 import java.nio.file.*;
 import java.util.List;
+import java.util.Optional;
 
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.*;
@@ -173,21 +174,35 @@ class GitDBTest implements WithAssertions {
     @Test
     void openRepo_whenGitDB_thenReturnGitDB() throws IOException {
         //given
-        final Path dir = gitDBRepo();
+        final Path dir = gitDBRepoPath();
         //when
         final GitDBLocal gitDB = GitDB.openLocal(dir);
         //then
         assertThat(gitDB).isNotNull();
     }
 
-    private Path gitDBRepo() throws IOException {
+    private Path gitDBRepoPath() throws IOException {
         final Path dbDir = dirDoesNotExist();
         GitDB.initLocal(dbDir);
         return dbDir;
     }
 
     // Given a valid GitDb handle
-    // When select a branch that doesn't exist then an exception is thrown
+    // When select a branch that doesn't exist then an empty Optional is returned
+    @Test
+    void selectBranch_branchNotExist_thenEmptyOptional() throws IOException {
+        //given
+        final GitDB gitDb = newGitDBRepo();
+        //when
+        final Optional<GitDBBranch> branch = gitDb.branch("unknown");
+        //then
+        assertThat(branch).isEmpty();
+    }
+
+    private GitDB newGitDBRepo() throws IOException {
+        return GitDB.initLocal(dirDoesNotExist());
+    }
+
     // When select a valid branch then a GitDbBranch is returned
 
     // Given a valid GitDbBranch handle