Add an acceptance test for pushing changes with Signed-off-by

I thought this functionality wasn't working, but while writing
this test I realised it was simply because my account had the
forge committer permission.

Change-Id: I1e5cf3b92ecbb2ba296cf9874c3350ea57a123ee

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/AbstractDaemonTest.java

@@ -317,6 +317,15 @@ public abstract class AbstractDaemonTest {
     projectCache.evict(config.getProject());
   }
 
+  protected void setUseSignedOffBy(InheritableBoolean value)
+      throws Exception {
+    MetaDataUpdate md = metaDataUpdateFactory.create(project);
+    ProjectConfig config = ProjectConfig.read(md);
+    config.getProject().setUseSignedOffBy(value);
+    config.commit(md);
+    projectCache.evict(config.getProject());
+  }
+
   protected void deny(String permission, AccountGroup.UUID id, String ref)
       throws Exception {
     ProjectConfig cfg = projectCache.checkedGet(project).getConfig();
@@ -362,6 +371,13 @@ public abstract class AbstractDaemonTest {
     saveProjectConfig(project, cfg);
   }
 
+  protected void blockForgeCommitter(Project.NameKey project, String ref)
+      throws Exception {
+    ProjectConfig cfg = projectCache.checkedGet(project).getConfig();
+    block(cfg, Permission.FORGE_COMMITTER, REGISTERED_USERS, ref);
+    saveProjectConfig(project, cfg);
+  }
+
   protected PushOneCommit.Result pushTo(String ref) throws GitAPIException,
       IOException {
     PushOneCommit push = pushFactory.create(db, admin.getIdent());

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/git/AbstractPushForReview.java

@@ -25,6 +25,7 @@ import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.TestAccount;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.extensions.api.projects.BranchInput;
+import com.google.gerrit.extensions.client.InheritableBoolean;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.EditInfo;
 import com.google.gerrit.extensions.common.LabelInfo;
@@ -343,4 +344,29 @@ public abstract class AbstractPushForReview extends AbstractDaemonTest {
     assertThat(c1.changeId).isEqualTo(c2.changeId);
     assertThat(c1.currentRevision).isEqualTo(c2.currentRevision);
   }
+
+  @Test
+  public void testPushCommitUsingSignedOffBy() throws Exception {
+    PushOneCommit push =
+        pushFactory.create(db, admin.getIdent(), PushOneCommit.SUBJECT,
+            "b.txt", "anotherContent");
+    PushOneCommit.Result r = push.to(git, "refs/for/master");
+    r.assertOkStatus();
+
+    setUseSignedOffBy(InheritableBoolean.TRUE);
+    blockForgeCommitter(project, "refs/heads/master");
+
+    push = pushFactory.create(db, admin.getIdent(),
+        PushOneCommit.SUBJECT + String.format(
+            "\n\nSigned-off-by: %s <%s>", admin.fullName, admin.email),
+        "b.txt", "anotherContent");
+    r = push.to(git, "refs/for/master");
+    r.assertOkStatus();
+
+    push = pushFactory.create(db, admin.getIdent(), PushOneCommit.SUBJECT,
+        "b.txt", "anotherContent");
+    r = push.to(git, "refs/for/master");
+    r.assertErrorStatus(
+        "not Signed-off-by author/committer/uploader in commit message footer");
+  }
 }