Add "--squash" option to MergeCommand

CQ: 6570
Bug: 351806
Change-Id: I5e47810376419264ecf4247b5a333af5c8945080
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

6 files changed, 430 insertions, 6 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java
index 3aec611f44..9b597d32da 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitCommandTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011, GitHub Inc.
+ * Copyright (C) 2011-2012, GitHub Inc.
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -44,6 +44,7 @@ package org.eclipse.jgit.api;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -68,7 +69,7 @@ import org.eclipse.jgit.util.FS;
 import org.junit.Test;
 
 /**
- * Unit tests of {@link CommitCommand}
+ * Unit tests of {@link CommitCommand}.
  */
 public class CommitCommandTest extends RepositoryTestCase {
 
@@ -365,4 +366,42 @@ public class CommitCommandTest extends RepositoryTestCase {
 		assertEquals(file1Size, cache.getEntry("file1.txt").getLength());
 		assertEquals(0, cache.getEntry("file2.txt").getLength());
 	}
+
+	@Test
+	public void commitAfterSquashMerge() throws Exception {
+		Git git = new Git(db);
+
+		writeTrashFile("file1", "file1");
+		git.add().addFilepattern("file1").call();
+		RevCommit first = git.commit().setMessage("initial commit").call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		createBranch(first, "refs/heads/branch1");
+		checkoutBranch("refs/heads/branch1");
+
+		writeTrashFile("file2", "file2");
+		git.add().addFilepattern("file2").call();
+		git.commit().setMessage("second commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		checkoutBranch("refs/heads/master");
+
+		MergeResult result = git.merge().include(db.getRef("branch1"))
+				.setSquash(true).call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+		assertEquals(MergeResult.MergeStatus.FAST_FORWARD_SQUASHED,
+				result.getMergeStatus());
+
+		// comment not set, should be inferred from SQUASH_MSG
+		RevCommit squashedCommit = git.commit().call();
+
+		assertEquals(1, squashedCommit.getParentCount());
+		assertNull(db.readSquashCommitMsg());
+		assertEquals("commit: Squashed commit of the following:", db
+				.getReflogReader(Constants.HEAD).getLastEntry().getComment());
+		assertEquals("commit: Squashed commit of the following:", db
+				.getReflogReader(db.getBranch()).getLastEntry().getComment());
+	}
 }
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
index 30a94520d1..c6875b4832 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2010, Stefan Lay <stefan.lay@sap.com>
- * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
+ * Copyright (C) 2010-2012, Christian Halstrick <christian.halstrick@sap.com>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -45,6 +45,7 @@ package org.eclipse.jgit.api;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -62,6 +63,9 @@ import org.eclipse.jgit.merge.ResolveMerger.MergeFailureReason;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
+import org.eclipse.jgit.util.GitDateFormatter;
+import org.eclipse.jgit.util.GitDateFormatter.Format;
+import org.junit.Before;
 import org.junit.Test;
 import org.junit.experimental.theories.DataPoints;
 import org.junit.experimental.theories.Theories;
@@ -74,6 +78,15 @@ public class MergeCommandTest extends RepositoryTestCase {
 	public static @DataPoints
 	MergeStrategy[] mergeStrategies = MergeStrategy.get();
 
+	private GitDateFormatter dateFormatter;
+
+	@Override
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		dateFormatter = new GitDateFormatter(Format.DEFAULT);
+	}
+
 	@Test
 	public void testMergeInItself() throws Exception {
 		Git git = new Git(db);
@@ -1096,6 +1109,180 @@ public class MergeCommandTest extends RepositoryTestCase {
 		assertFalse(canExecute(git, "mergeableButDirty"));
 	}
 
+	@Test
+	public void testSquashFastForward() throws Exception {
+		Git git = new Git(db);
+
+		writeTrashFile("file1", "file1");
+		git.add().addFilepattern("file1").call();
+		RevCommit first = git.commit().setMessage("initial commit").call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		createBranch(first, "refs/heads/branch1");
+		checkoutBranch("refs/heads/branch1");
+
+		writeTrashFile("file2", "file2");
+		git.add().addFilepattern("file2").call();
+		RevCommit second = git.commit().setMessage("second commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		writeTrashFile("file3", "file3");
+		git.add().addFilepattern("file3").call();
+		RevCommit third = git.commit().setMessage("third commit").call();
+		assertTrue(new File(db.getWorkTree(), "file3").exists());
+
+		checkoutBranch("refs/heads/master");
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertFalse(new File(db.getWorkTree(), "file2").exists());
+		assertFalse(new File(db.getWorkTree(), "file3").exists());
+
+		MergeResult result = git.merge().include(db.getRef("branch1"))
+				.setSquash(true).call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+		assertTrue(new File(db.getWorkTree(), "file3").exists());
+		assertEquals(MergeResult.MergeStatus.FAST_FORWARD_SQUASHED,
+				result.getMergeStatus());
+		assertEquals(first, result.getNewHead()); // HEAD didn't move
+		assertEquals(first, db.resolve(Constants.HEAD + "^{commit}"));
+
+		assertEquals(
+				"Squashed commit of the following:\n\ncommit "
+						+ third.getName()
+						+ "\nAuthor: "
+						+ third.getAuthorIdent().getName()
+						+ " <"
+						+ third.getAuthorIdent().getEmailAddress()
+						+ ">\nDate:   "
+						+ dateFormatter.formatDate(third
+								.getAuthorIdent())
+						+ "\n\n\tthird commit\n\ncommit "
+						+ second.getName()
+						+ "\nAuthor: "
+						+ second.getAuthorIdent().getName()
+						+ " <"
+						+ second.getAuthorIdent().getEmailAddress()
+						+ ">\nDate:   "
+						+ dateFormatter.formatDate(second
+								.getAuthorIdent()) + "\n\n\tsecond commit\n",
+				db.readSquashCommitMsg());
+		assertNull(db.readMergeCommitMsg());
+
+		Status stat = git.status().call();
+		assertEquals(StatusCommandTest.set("file2", "file3"), stat.getAdded());
+	}
+
+	@Test
+	public void testSquashMerge() throws Exception {
+		Git git = new Git(db);
+
+		writeTrashFile("file1", "file1");
+		git.add().addFilepattern("file1").call();
+		RevCommit first = git.commit().setMessage("initial commit").call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		createBranch(first, "refs/heads/branch1");
+
+		writeTrashFile("file2", "file2");
+		git.add().addFilepattern("file2").call();
+		RevCommit second = git.commit().setMessage("second commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		checkoutBranch("refs/heads/branch1");
+
+		writeTrashFile("file3", "file3");
+		git.add().addFilepattern("file3").call();
+		RevCommit third = git.commit().setMessage("third commit").call();
+		assertTrue(new File(db.getWorkTree(), "file3").exists());
+
+		checkoutBranch("refs/heads/master");
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+		assertFalse(new File(db.getWorkTree(), "file3").exists());
+
+		MergeResult result = git.merge().include(db.getRef("branch1"))
+				.setSquash(true).call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+		assertTrue(new File(db.getWorkTree(), "file3").exists());
+		assertEquals(MergeResult.MergeStatus.MERGED_SQUASHED,
+				result.getMergeStatus());
+		assertEquals(second, result.getNewHead()); // HEAD didn't move
+		assertEquals(second, db.resolve(Constants.HEAD + "^{commit}"));
+
+		assertEquals(
+				"Squashed commit of the following:\n\ncommit "
+						+ third.getName()
+						+ "\nAuthor: "
+						+ third.getAuthorIdent().getName()
+						+ " <"
+						+ third.getAuthorIdent().getEmailAddress()
+						+ ">\nDate:   "
+						+ dateFormatter.formatDate(third
+								.getAuthorIdent()) + "\n\n\tthird commit\n",
+				db.readSquashCommitMsg());
+		assertNull(db.readMergeCommitMsg());
+
+		Status stat = git.status().call();
+		assertEquals(StatusCommandTest.set("file3"), stat.getAdded());
+	}
+
+	@Test
+	public void testSquashMergeConflict() throws Exception {
+		Git git = new Git(db);
+
+		writeTrashFile("file1", "file1");
+		git.add().addFilepattern("file1").call();
+		RevCommit first = git.commit().setMessage("initial commit").call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		createBranch(first, "refs/heads/branch1");
+
+		writeTrashFile("file2", "master");
+		git.add().addFilepattern("file2").call();
+		RevCommit second = git.commit().setMessage("second commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		checkoutBranch("refs/heads/branch1");
+
+		writeTrashFile("file2", "branch");
+		git.add().addFilepattern("file2").call();
+		RevCommit third = git.commit().setMessage("third commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		checkoutBranch("refs/heads/master");
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		MergeResult result = git.merge().include(db.getRef("branch1"))
+				.setSquash(true).call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+		assertEquals(MergeResult.MergeStatus.CONFLICTING,
+				result.getMergeStatus());
+		assertNull(result.getNewHead());
+		assertEquals(second, db.resolve(Constants.HEAD + "^{commit}"));
+
+		assertEquals(
+				"Squashed commit of the following:\n\ncommit "
+						+ third.getName()
+						+ "\nAuthor: "
+						+ third.getAuthorIdent().getName()
+						+ " <"
+						+ third.getAuthorIdent().getEmailAddress()
+						+ ">\nDate:   "
+						+ dateFormatter.formatDate(third
+								.getAuthorIdent()) + "\n\n\tthird commit\n",
+				db.readSquashCommitMsg());
+		assertEquals("\nConflicts:\n\tfile2\n", db.readMergeCommitMsg());
+
+		Status stat = git.status().call();
+		assertEquals(StatusCommandTest.set("file2"), stat.getConflicting());
+	}
+
 	private void setExecutable(Git git, String path, boolean executable) {
 		FS.DETECTED.setExecute(
 				new File(git.getRepository().getWorkTree(), path), executable);
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java
index 0806cf0dd0..c55775c9fe 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/ResetCommandTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011, Chris Aniszczyk <caniszczyk@gmail.com>
+ * Copyright (C) 2011-2012, Chris Aniszczyk <caniszczyk@gmail.com>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -46,6 +46,7 @@ import static org.eclipse.jgit.api.ResetCommand.ResetType.HARD;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -359,6 +360,37 @@ public class ResetCommandTest extends RepositoryTestCase {
 		assertTrue(head.equals(secondCommit));
 	}
 
+	@Test
+	public void testHardResetAfterSquashMerge() throws Exception {
+		Git g = new Git(db);
+
+		writeTrashFile("file1", "file1");
+		g.add().addFilepattern("file1").call();
+		RevCommit first = g.commit().setMessage("initial commit").call();
+
+		assertTrue(new File(db.getWorkTree(), "file1").exists());
+		createBranch(first, "refs/heads/branch1");
+		checkoutBranch("refs/heads/branch1");
+
+		writeTrashFile("file2", "file2");
+		g.add().addFilepattern("file2").call();
+		g.commit().setMessage("second commit").call();
+		assertTrue(new File(db.getWorkTree(), "file2").exists());
+
+		checkoutBranch("refs/heads/master");
+
+		MergeResult result = g.merge().include(db.getRef("branch1"))
+				.setSquash(true).call();
+
+		assertEquals(MergeResult.MergeStatus.FAST_FORWARD_SQUASHED,
+				result.getMergeStatus());
+		assertNotNull(db.readSquashCommitMsg());
+
+		g.reset().setMode(ResetType.HARD).setRef(first.getName()).call();
+
+		assertNull(db.readSquashCommitMsg());
+	}
+
 	private void assertReflog(ObjectId prevHead, ObjectId head)
 			throws IOException {
 		// Check the reflog for HEAD
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/MergeHeadMsgTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/MergeHeadMsgTest.java
index 4e128e7f25..ed1f96776b 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/MergeHeadMsgTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/MergeHeadMsgTest.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
+ * Copyright (C) 2010-2012 Christian Halstrick <christian.halstrick@sap.com>
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
@@ -78,7 +78,7 @@ public class MergeHeadMsgTest extends RepositoryTestCase {
 		assertEquals(db.readMergeHeads().size(), 2);
 		assertEquals(db.readMergeHeads().get(0), ObjectId.zeroId());
 		assertEquals(db.readMergeHeads().get(1), ObjectId.fromString(sampleId));
-		db.writeMergeHeads(Collections.EMPTY_LIST);
+		db.writeMergeHeads(Collections.<ObjectId> emptyList());
 		assertEquals(read(new File(db.getDirectory(), "MERGE_HEAD")), "");
 		assertEquals(db.readMergeHeads(), null);
 		fos = new FileOutputStream(new File(db.getDirectory(),
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/SquashCommitMsgTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/SquashCommitMsgTest.java
new file mode 100644
index 0000000000..4374e4747e
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/SquashCommitMsgTest.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2012, IBM Corporation and others.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.lib;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+
+import org.junit.Test;
+
+public class SquashCommitMsgTest extends RepositoryTestCase {
+	private static final String squashMsg = "squashed commit";
+
+	@Test
+	public void testReadWriteMergeMsg() throws IOException {
+		assertEquals(db.readSquashCommitMsg(), null);
+		assertFalse(new File(db.getDirectory(), Constants.SQUASH_MSG).exists());
+		db.writeSquashCommitMsg(squashMsg);
+		assertEquals(squashMsg, db.readSquashCommitMsg());
+		assertEquals(read(new File(db.getDirectory(), Constants.SQUASH_MSG)),
+				squashMsg);
+		db.writeSquashCommitMsg(null);
+		assertEquals(db.readSquashCommitMsg(), null);
+		assertFalse(new File(db.getDirectory(), Constants.SQUASH_MSG).exists());
+		FileOutputStream fos = new FileOutputStream(new File(db.getDirectory(),
+				Constants.SQUASH_MSG));
+		try {
+			fos.write(squashMsg.getBytes(Constants.CHARACTER_ENCODING));
+		} finally {
+			fos.close();
+		}
+		assertEquals(db.readSquashCommitMsg(), squashMsg);
+	}
+}
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SquashMessageFormatterTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SquashMessageFormatterTest.java
new file mode 100644
index 0000000000..4274d8baff
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SquashMessageFormatterTest.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2012, IBM Corporation and others.
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.merge;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.SampleDataRepositoryTestCase;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.util.GitDateFormatter;
+import org.eclipse.jgit.util.GitDateFormatter.Format;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test construction of squash message by {@link SquashMessageFormatterTest}.
+ */
+public class SquashMessageFormatterTest extends SampleDataRepositoryTestCase {
+	private GitDateFormatter dateFormatter;
+	private SquashMessageFormatter msgFormatter;
+	private RevCommit revCommit;
+
+	@Override
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		dateFormatter = new GitDateFormatter(Format.DEFAULT);
+		msgFormatter = new SquashMessageFormatter();
+	}
+
+	@Test
+	public void testCommit() throws Exception {
+		Git git = new Git(db);
+		revCommit = git.commit().setMessage("squash_me").call();
+
+		Ref master = db.getRef("refs/heads/master");
+		String message = msgFormatter.format(Arrays.asList(revCommit), master);
+		assertEquals(
+				"Squashed commit of the following:\n\ncommit "
+						+ revCommit.getName() + "\nAuthor: "
+						+ revCommit.getAuthorIdent().getName() + " <"
+						+ revCommit.getAuthorIdent().getEmailAddress()
+						+ ">\nDate:   " + dateFormatter.formatDate(author)
+						+ "\n\n\tsquash_me\n", message);
+	}
+}