Fixed: EGit allows starting features with diverging develop branches

In comparison, when the upstream develop branch is ahead of the local
develop branch command line Gitflow (AVH) raises an error:
$ git flow feature start "foo"
Branches 'develop' and 'origin/develop' have diverged.
Fatal: And branch 'develop' may be fast-forwarded.

Adjusted JUnit tests to cover new code.

Change-Id: I2629301539e96b3911987ad300a7ed538b1d0516

3 files changed, 107 insertions, 1 deletions

diff --git a/org.eclipse.egit.gitflow.test/META-INF/MANIFEST.MF b/org.eclipse.egit.gitflow.test/META-INF/MANIFEST.MF
index e0bbb1d029..c68c944eca 100644
--- a/org.eclipse.egit.gitflow.test/META-INF/MANIFEST.MF
+++ b/org.eclipse.egit.gitflow.test/META-INF/MANIFEST.MF
@@ -9,5 +9,7 @@ Bundle-RequiredExecutionEnvironment: JavaSE-1.8
 Import-Package: org.eclipse.egit.core;version="[5.1.0,5.2.0)",
  org.eclipse.egit.core.test;version="[5.1.0,5.2.0)",
  org.eclipse.jgit.junit;version="[5.1.0,5.2.0)",
+ org.hamcrest;version="[1.1.0,1.2.0)",
+ org.junit.rules;version="[4.12.0,4.13.0)",
  org.junit;version="[4.3.0,5.0.0)"
 Require-Bundle: org.eclipse.core.resources
diff --git a/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/AbstractDualRepositoryTestCase.java b/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/AbstractDualRepositoryTestCase.java
index 6dd6a1dc93..9ceeafc212 100644
--- a/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/AbstractDualRepositoryTestCase.java
+++ b/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/AbstractDualRepositoryTestCase.java
@@ -50,7 +50,7 @@ public class AbstractDualRepositoryTestCase extends DualRepositoryTestCase {
 
 	private File workdir2;
 
-	String projectName = "FeaturePublishTest";
+	String projectName = "FeatureTest";
 
 	protected RevCommit initialCommit;
 
diff --git a/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/FeatureStartOperationDivergingTest.java b/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/FeatureStartOperationDivergingTest.java
new file mode 100644
index 0000000000..ffb2d31554
--- /dev/null
+++ b/org.eclipse.egit.gitflow.test/src/org/eclipse/egit/gitflow/op/FeatureStartOperationDivergingTest.java
@@ -0,0 +1,104 @@
+/*******************************************************************************
+ * Copyright (C) 2018, Max Hohenegger <eclipse@hohenegger.eu>
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.egit.gitflow.op;
+
+import static org.eclipse.jgit.lib.Constants.DEFAULT_REMOTE_NAME;
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Collections;
+
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.egit.core.op.FetchOperation;
+import org.eclipse.egit.core.op.PullOperation;
+import org.eclipse.egit.gitflow.GitFlowRepository;
+import org.eclipse.jgit.transport.RemoteConfig;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+public class FeatureStartOperationDivergingTest extends AbstractDualRepositoryTestCase {
+	@Rule
+	public ExpectedException expectedException = ExpectedException.none();
+
+	@Test
+	public void testFeatureStart_localDevelopBehind() throws Exception {
+		GitFlowRepository gfRepo1 = new GitFlowRepository(
+				repository1.getRepository());
+		GitFlowRepository gfRepo2 = new GitFlowRepository(
+				repository2.getRepository());
+
+		fetch(gfRepo2);
+		init(gfRepo2);
+		setDevelopRemote(gfRepo1, gfRepo2);
+
+		repository1.commit("origin/develop is 1 commit ahead");
+
+		FeatureStartOperation featureStartOperation = new FeatureStartOperation(
+				gfRepo2, MY_FEATURE);
+
+		expectedException.expect(CoreException.class);
+		expectedException.expectMessage(
+				"Branches 'develop' and 'origin/develop' have diverged."
+						+ "\nAnd branch 'develop' may be fast-forwarded.");
+		featureStartOperation.execute(null);
+	}
+
+	@Test
+	public void testFeatureStart_localDevelopAhead() throws Exception {
+		GitFlowRepository gfRepo1 = new GitFlowRepository(
+				repository1.getRepository());
+		GitFlowRepository gfRepo2 = new GitFlowRepository(
+				repository2.getRepository());
+
+		fetch(gfRepo2);
+		init(gfRepo2);
+		setDevelopRemote(gfRepo1, gfRepo2);
+
+		new PullOperation(Collections.singleton(repository2.getRepository()),
+				-1).execute(null);
+
+		repository2.commit("develop is 1 commit ahead");
+
+		FeatureStartOperation featureStartOperation = new FeatureStartOperation(
+				gfRepo2, MY_FEATURE);
+		featureStartOperation.execute(null);
+
+		assertEquals("feature branch successfully created and checked out",
+				gfRepo2.getConfig().getFullFeatureBranchName(MY_FEATURE),
+				repository2.getRepository().getFullBranch());
+	}
+
+	private void fetch(GitFlowRepository gfRepo2)
+			throws InvocationTargetException {
+		RemoteConfig config = gfRepo2.getConfig().getDefaultRemoteConfig();
+		FetchOperation fetchOperation = new FetchOperation(
+				gfRepo2.getRepository(), config,
+				-1, false);
+		fetchOperation.run(null);
+	}
+
+	private void setDevelopRemote(GitFlowRepository remote,
+			GitFlowRepository local) throws IOException {
+		String develop = local.getConfig().getDevelop();
+		String developFull = remote.getConfig().getDevelopFull();
+		local.setRemote(develop, DEFAULT_REMOTE_NAME);
+		local.setUpstreamBranchName(develop, developFull);
+	}
+
+	private void init(GitFlowRepository gfRepo2) throws CoreException {
+		InitOperation initOperation = new InitOperation(
+				gfRepo2.getRepository());
+		initOperation.execute(null);
+	}
+
+}