added testcase for force push [JENKINS-24082]

src/test/java/hudson/plugins/git/GitPublisherTest.java

@@ -39,7 +39,9 @@
 import hudson.scm.NullSCM;
 import hudson.tasks.BuildStepDescriptor;
 import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
 import org.jvnet.hudson.test.Bug;
+import org.jvnet.hudson.test.Issue;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -132,6 +134,40 @@ public void testMergeAndPush() throws Exception {
         assertEquals(sha1, testRepo.git.revParse(Constants.HEAD).name());
 
     }
+
+    @Issue("JENKINS-24082")
+    public void testForcePush() throws Exception {
+    	FreeStyleProject project = setupSimpleProject("master");
+
+        GitSCM scm = new GitSCM(
+                createRemoteRepositories(),
+                Collections.singletonList(new BranchSpec("*")),
+                false, Collections.<SubmoduleConfig>emptyList(),
+                null, null,
+                Collections.<GitSCMExtension>emptyList());
+        project.setScm(scm);
+
+        project.getPublishersList().add(new GitPublisher(
+                Collections.<TagToPush>emptyList(),
+                Collections.singletonList(new BranchToPush("origin", "otherbranch")),
+                Collections.<NoteToPush>emptyList(),
+                true, true, true));
+
+        commit("commitFile", johnDoe, "Initial Commit");
+
+        testRepo.git.branch("otherbranch");
+        testRepo.git.checkout("otherbranch");
+        commit("otherCommitFile", johnDoe, "commit lost on force push");
+
+        testRepo.git.checkout("master");
+        commit("commitFile2", johnDoe, "commit to be pushed");
+
+        ObjectId expectedCommit = testRepo.git.revParse("master");
+
+        build(project, Result.SUCCESS, "commitFile");
+
+        assertEquals(expectedCommit, testRepo.git.revParse("otherbranch"));
+    }
 
     /**
      * Fix push to remote when skipTag is enabled