DiffCommandTest: Open Git and RevWalk in try-with-resource

Change-Id: I966f7e5053651661abc7de63c968e1f5bf2de464
Signed-off-by: David Pursehouse <david.pursehouse@sonymobile.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DiffCommandTest.java

@@ -70,7 +70,7 @@ public class DiffCommandTest extends RepositoryTestCase {
 		File folder = new File(db.getWorkTree(), "folder");
 		folder.mkdir();
 		write(new File(folder, "folder.txt"), "folder");
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			git.commit().setMessage("Initial commit").call();
 			write(new File(folder, "folder.txt"), "folder change");
@@ -97,13 +97,14 @@ public class DiffCommandTest extends RepositoryTestCase {
 					+ "\\ No newline at end of file\n";
 			assertEquals(expected.toString(), actual);
 		}
+	}
 
 	@Test
 	public void testDiffCached() throws Exception {
 		write(new File(db.getWorkTree(), "test.txt"), "test");
 		File folder = new File(db.getWorkTree(), "folder");
 		folder.mkdir();
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			git.commit().setMessage("Initial commit").call();
 			write(new File(folder, "folder.txt"), "folder");
@@ -131,6 +132,7 @@ public class DiffCommandTest extends RepositoryTestCase {
 					+ "\\ No newline at end of file\n";
 			assertEquals(expected.toString(), actual);
 		}
+	}
 
 	@Test
 	public void testDiffTwoCommits() throws Exception {
@@ -138,7 +140,7 @@ public class DiffCommandTest extends RepositoryTestCase {
 		File folder = new File(db.getWorkTree(), "folder");
 		folder.mkdir();
 		write(new File(folder, "folder.txt"), "folder");
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			git.commit().setMessage("Initial commit").call();
 			write(new File(folder, "folder.txt"), "folder change");
@@ -179,19 +181,19 @@ public class DiffCommandTest extends RepositoryTestCase {
 					+ "\\ No newline at end of file\n";
 			assertEquals(expected.toString(), actual);
 		}
+	}
 
 	@Test
 	public void testDiffWithPrefixes() throws Exception {
 		write(new File(db.getWorkTree(), "test.txt"), "test");
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			git.commit().setMessage("Initial commit").call();
 			write(new File(db.getWorkTree(), "test.txt"), "test change");
 
 			OutputStream out = new ByteArrayOutputStream();
 			git.diff().setOutputStream(out).setSourcePrefix("old/")
-				.setDestinationPrefix("new/")
+					.setDestinationPrefix("new/").call();
-				.call();
 
 			String actual = out.toString();
 			String expected = "diff --git old/test.txt new/test.txt\n"
@@ -201,20 +203,20 @@ public class DiffCommandTest extends RepositoryTestCase {
 					+ "\\ No newline at end of file\n";
 			assertEquals(expected.toString(), actual);
 		}
+	}
 
 	@Test
 	public void testDiffWithNegativeLineCount() throws Exception {
 		write(new File(db.getWorkTree(), "test.txt"),
 				"0\n1\n2\n3\n4\n5\n6\n7\n8\n9");
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			git.commit().setMessage("Initial commit").call();
 			write(new File(db.getWorkTree(), "test.txt"),
 					"0\n1\n2\n3\n4a\n5\n6\n7\n8\n9");
 
 			OutputStream out = new ByteArrayOutputStream();
-		git.diff().setOutputStream(out).setContextLines(1)
+			git.diff().setOutputStream(out).setContextLines(1).call();
-				.call();
 
 			String actual = out.toString();
 			String expected = "diff --git a/test.txt b/test.txt\n"
@@ -223,12 +225,13 @@ public class DiffCommandTest extends RepositoryTestCase {
 					+ "+4a\n" + " 5\n";
 			assertEquals(expected.toString(), actual);
 		}
+	}
 
 	@Test
 	public void testNoOutputStreamSet() throws Exception {
 		File file = writeTrashFile("test.txt", "a");
 		assertTrue(file.setLastModified(file.lastModified() - 5000));
-		Git git = new Git(db);
+		try (Git git = new Git(db)) {
 			git.add().addFilepattern(".").call();
 			write(file, "b");
 
@@ -240,6 +243,7 @@ public class DiffCommandTest extends RepositoryTestCase {
 			assertEquals("test.txt", diff.getOldPath());
 			assertEquals("test.txt", diff.getNewPath());
 		}
+	}
 
 	private AbstractTreeIterator getTreeIterator(String name)
 			throws IOException {
@@ -247,8 +251,9 @@ public class DiffCommandTest extends RepositoryTestCase {
 		if (id == null)
 			throw new IllegalArgumentException(name);
 		final CanonicalTreeParser p = new CanonicalTreeParser();
-		try (ObjectReader or = db.newObjectReader()) {
+		try (ObjectReader or = db.newObjectReader();
-			p.reset(or, new RevWalk(db).parseTree(id));
+				RevWalk rw = new RevWalk(db)) {
+			p.reset(or, rw.parseTree(id));
 			return p;
 		}
 	}