Add unit test for git diff command

scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitDiffCommandTest.java

@@ -0,0 +1,45 @@
+package sonia.scm.repository.spi;
+
+import org.junit.Test;
+
+import java.io.ByteArrayOutputStream;
+
+import static org.junit.Assert.assertEquals;
+
+public class GitDiffCommandTest extends AbstractGitCommandTestBase {
+
+  private static final String DIFF_LATEST_COMMIT_TEST_BRANCH = "diff --git a/a.txt b/a.txt\n" +
+    "index 7898192..1dc60c7 100644\n" +
+    "--- a/a.txt\n" +
+    "+++ b/a.txt\n" +
+    "@@ -1 +1 @@\n" +
+    "-a\n" +
+    "+a and b\n" +
+    "diff --git a/b.txt b/b.txt\n" +
+    "deleted file mode 100644\n" +
+    "index 6178079..0000000\n" +
+    "--- a/b.txt\n" +
+    "+++ /dev/null\n" +
+    "@@ -1 +0,0 @@\n" +
+    "-b\n";
+
+  @Test
+  public void diffForOneRevisionShouldCreateDiff() {
+    GitDiffCommand gitDiffCommand = new GitDiffCommand(createContext(), repository);
+    DiffCommandRequest diffCommandRequest = new DiffCommandRequest();
+    diffCommandRequest.setRevision("3f76a12f08a6ba0dc988c68b7f0b2cd190efc3c4");
+    ByteArrayOutputStream output = new ByteArrayOutputStream();
+    gitDiffCommand.getDiffResult(diffCommandRequest, output);
+    assertEquals(DIFF_LATEST_COMMIT_TEST_BRANCH, output.toString());
+  }
+
+  @Test
+  public void diffForOneBranchShouldCreateDiff() {
+    GitDiffCommand gitDiffCommand = new GitDiffCommand(createContext(), repository);
+    DiffCommandRequest diffCommandRequest = new DiffCommandRequest();
+    diffCommandRequest.setRevision("test-branch");
+    ByteArrayOutputStream output = new ByteArrayOutputStream();
+    gitDiffCommand.getDiffResult(diffCommandRequest, output);
+    assertEquals(DIFF_LATEST_COMMIT_TEST_BRANCH, output.toString());
+  }
+}