Add Defer functionality

Html plugin adds Defer button and dropdown search to UI.
Defer REST API added to java plugin.

Change-Id: I49f70c1bdd1cb8609e4f2a206e937eb4a1a66778
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

6 files changed, 589 insertions, 2 deletions

diff --git a/qt-gerrit-ui-plugin/qt-gerrit-ui-plugin.html b/qt-gerrit-ui-plugin/qt-gerrit-ui-plugin.html
new file mode 100644
index 0000000..2d42702
--- /dev/null
+++ b/qt-gerrit-ui-plugin/qt-gerrit-ui-plugin.html
@@ -0,0 +1,190 @@
+//
+// Copyright (C) 2018 The Qt Company
+//
+// This plugin provides UI customization for codereview.qt-project.org
+//
+
+<dom-module id="qt-gerrit-ui-plugin">
+    <script>
+        'use strict';
+
+        var BUTTONS = {
+            'gerrit-plugin-qt-workflow~defer' : {
+                header: 'Defer the change?',
+                action_name: 'defer'
+            }
+        };
+
+        Gerrit.install(plugin => {
+
+            plugin.custom_popup = null;
+            plugin.custom_popup_promise = null;
+            plugin.buttons = null;
+
+            function htmlToElement(html) {
+                var template = document.createElement('template');
+                html = html.trim(); // No white space
+                template.innerHTML = html;
+                return template.content.firstChild;
+            }
+
+            // Customize header changes dropdown menu
+            plugin.hook('header-dropdown-Changes').onAttached(element => {
+                // this is ugly, but there is no API for this
+                var ul_elem = element.content.children[1].children[0].children[0].children[0];
+                var li_elem;
+                var link_elem;
+
+                li_elem = htmlToElement(ul_elem.children[1].outerHTML);
+                link_elem = li_elem.children[0].children[1];
+                link_elem.text = 'Deferred';
+                link_elem.href = '/q/status:deferred';
+                ul_elem.insertBefore(li_elem, ul_elem.children[3]);
+            });
+
+            // Customize change view
+            plugin.on('showchange', function(changeInfo, revisionInfo) {
+                plugin.ca = plugin.changeActions();
+
+                // Remove any existing buttons
+                if (plugin.buttons) {
+                    for (var key in BUTTONS) {
+                        if (BUTTONS.hasOwnProperty(key)) {
+                            if(typeof plugin.buttons[key] !== 'undefined' && plugin.buttons[key] !== null) {
+                                plugin.ca.removeTapListener(plugin.buttons[key], (param) => {} );
+                                plugin.ca.remove(plugin.buttons[key]);
+                                plugin.buttons[key] = null;
+                            }
+                        }
+                    }
+                } else plugin.buttons = [];
+
+                // Add buttons based on server response
+                for (var key in BUTTONS) {
+                    if (BUTTONS.hasOwnProperty(key)) {
+                        var action = plugin.ca.getActionDetails(key);
+                        if (action) {
+                            // hide dropdown action
+                            plugin.ca.setActionHidden(action.__type, action.__key, true);
+
+                            // add button
+                            plugin.buttons[key] = plugin.ca.add(action.__type, action.label);
+                            plugin.ca.setTitle(plugin.buttons[key], action.title);
+                            plugin.ca.addTapListener(plugin.buttons[key], buttonEventCallback);
+                        }
+                    }
+                }
+
+                function buttonEventCallback(event) {
+                    var button_key = event.type.substring(0, event.type.indexOf('-tap'));
+                    var button_action = null;
+                    var button_index;
+                    for (var k in plugin.buttons) {
+                        if (plugin.buttons[k] === button_key) {
+                            button_action = plugin.ca.getActionDetails(k);
+                            button_index = k;
+                            break;
+                        }
+                    }
+
+                    if (button_action) {
+                        plugin.popup('qt-gerrit-ui-confirm-dialog').then( (param) => {
+                            plugin.custom_popup_promise = param;
+                            plugin.custom_popup.set('header', BUTTONS[button_index].header);
+                            plugin.custom_popup.set('subject', changeInfo.subject);
+                            plugin.custom_popup.set('action_name', BUTTONS[button_index].action_name);
+                            plugin.custom_popup.set('api_url', button_action.__url);
+                        }).catch( (param) => { console.log('unexpected error: promise failed');});
+                    } else console.log('unexpected error: no action');
+                }
+            });
+        });
+    </script>
+</dom-module>
+
+<dom-module id="qt-gerrit-ui-confirm-dialog">
+    <template>
+        <style include="shared-styles">
+            #dialog {
+                min-width: 40em;
+            }
+            p {
+                margin-bottom: 1em;
+            }
+            @media screen and (max-width: 50em) {
+                #dialog {
+                      min-width: inherit;
+                      width: 100%;
+                }
+            }
+        </style>
+        <gr-dialog
+            id="dialog"
+            confirm-label="Continue"
+            confirm-on-enter
+            on-cancel="_handleCancelTap"
+            on-confirm="_handleConfirmTap">
+            <div class="header" slot="header">[[header]]</div>
+            <div class="main" slot="main">
+                <p>Ready to [[action_name]] &ldquo;<strong>[[subject]]</strong>&rdquo;?</p>
+                <p class="main" style="color: red;font-weight: bold;">[[errorMessage]]</p>
+            </div>
+        </gr-dialog>
+    </template>
+    <script>
+        'use strict';
+
+        var qtgerrituiconfirmdialog = Polymer({
+            is: 'qt-gerrit-ui-confirm-dialog',
+
+            properties: {
+                header: {
+                    type: String,
+                    value: '...wait...'
+                },
+                action_name: {
+                    type: String,
+                    value: ''
+                },
+                api_url: {
+                    type: String,
+                    value: ''
+                },
+                subject: {
+                    type: String,
+                    value: ''
+                },
+                errorMessage: {
+                    type: String,
+                    value: ''
+                }
+            },
+
+            attached: function() {
+                this.plugin.custom_popup = this;
+            },
+
+            resetFocus(e) {
+                this.$.dialog.resetFocus();
+            },
+
+            _handleConfirmTap(e) {
+                e.preventDefault();
+                this.plugin.restApi().post(this.get('api_url'), {})
+                    .then((ok_resp) => {
+                        this.plugin.custom_popup_promise.close();
+                        this.plugin.custom_popup_promise = null;
+                        window.location.reload(true);
+                    }).catch((failed_resp) => {
+                        this.set('errorMessage', 'FAILED: ' + failed_resp);
+                    });
+            },
+
+            _handleCancelTap(e) {
+                e.preventDefault();
+                this.plugin.custom_popup_promise.close();
+                this.plugin.custom_popup_promise = null;
+            },
+        });
+    </script>
+</dom-module>
diff --git a/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtChangeUpdateOp.java b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtChangeUpdateOp.java
new file mode 100644
index 0000000..491e896
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtChangeUpdateOp.java
@@ -0,0 +1,92 @@
+//
+// Copyright (C) 2018 The Qt Company
+//
+
+package com.googlesource.gerrit.plugins.qtcodereview;
+
+import com.google.common.base.Strings;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.ChangeMessage;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.server.ChangeMessagesUtil;
+import com.google.gerrit.server.notedb.ChangeUpdate;
+import com.google.gerrit.server.update.BatchUpdateOp;
+import com.google.gerrit.server.update.ChangeContext;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+import java.io.IOException;
+
+public class QtChangeUpdateOp implements BatchUpdateOp {
+
+    public interface Factory {
+        QtChangeUpdateOp create(Change.Status newStatus,
+                                @Assisted("defaultMessage") String defaultMessage,
+                                @Assisted("inputMessage") String inputMessage,
+                                @Assisted("tag") String tag);
+    }
+
+    private final Change.Status newStatus;
+    private final String defaultMessage;
+    private final String inputMessage;
+    private final String tag;
+
+    private Change change;
+
+    private final ChangeMessagesUtil cmUtil;
+
+
+    @Inject
+    QtChangeUpdateOp(ChangeMessagesUtil cmUtil,
+                     @Nullable @Assisted Change.Status newStatus,
+                     @Nullable @Assisted("defaultMessage") String defaultMessage,
+                     @Nullable @Assisted("inputMessage") String inputMessage,
+                     @Nullable @Assisted("tag") String tag) {
+        this.cmUtil = cmUtil;
+        this.newStatus = newStatus;
+        this.defaultMessage = defaultMessage;
+        this.inputMessage = inputMessage;
+        this.tag = tag;
+    }
+
+    public Change getChange() {
+        return change;
+    }
+
+    @Override
+    public boolean updateChange(ChangeContext ctx) throws OrmException, IOException, ResourceConflictException {
+        boolean updated = false;
+        change = ctx.getChange();
+        PatchSet.Id psId = change.currentPatchSetId();
+        ChangeUpdate update = ctx.getUpdate(psId);
+
+        if (newStatus != null) {
+            change.setStatus(newStatus);
+            updated = true;
+        }
+
+        if (updated == true) {
+            change.setLastUpdatedOn(ctx.getWhen());
+        }
+
+        if (defaultMessage != null) {
+            cmUtil.addChangeMessage(ctx.getDb(), update, newMessage(ctx));
+            updated = true;
+        }
+
+        return updated;
+    }
+
+    private ChangeMessage newMessage(ChangeContext ctx) {
+        StringBuilder msg = new StringBuilder();
+        msg.append(defaultMessage);
+        if (!Strings.nullToEmpty(inputMessage).trim().isEmpty()) {
+            msg.append("\n\n");
+            msg.append(inputMessage.trim());
+        }
+        return ChangeMessagesUtil.newMessage(ctx, msg.toString(), tag);
+    }
+
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtDefer.java b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtDefer.java
new file mode 100644
index 0000000..30b218f
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtDefer.java
@@ -0,0 +1,128 @@
+//
+// Copyright (C) 2019 The Qt Company
+// Modified from https://gerrit.googlesource.com/gerrit/+/refs/heads/stable-2.16/java/com/google/gerrit/server/restapi/change/Abandon.java
+//
+// Copyright (C) 2012 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.qtcodereview;
+
+import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.extensions.api.changes.AbandonInput;
+import com.google.gerrit.extensions.common.ChangeInfo;
+import com.google.gerrit.extensions.restapi.ResourceConflictException;
+import com.google.gerrit.extensions.restapi.RestApiException;
+import com.google.gerrit.extensions.webui.UiAction;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ChangeUtil;
+import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.change.ChangeJson;
+import com.google.gerrit.server.change.ChangeResource;
+import com.google.gerrit.server.permissions.ChangePermission;
+import com.google.gerrit.server.permissions.PermissionBackendException;
+import com.google.gerrit.server.update.BatchUpdate;
+import com.google.gerrit.server.update.RetryHelper;
+import com.google.gerrit.server.update.RetryingRestModifyView;
+import com.google.gerrit.server.update.UpdateException;
+import com.google.gerrit.server.util.time.TimeUtil;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+import java.io.IOException;
+
+
+@Singleton
+class QtDefer extends RetryingRestModifyView<ChangeResource, AbandonInput, ChangeInfo>
+              implements UiAction<ChangeResource> {
+
+    private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+    private final Provider<ReviewDb> dbProvider;
+    private final ChangeJson.Factory json;
+    private final PatchSetUtil psUtil;
+    private final QtChangeUpdateOp.Factory qtUpdateFactory;
+
+    @Inject
+    QtDefer(Provider<ReviewDb> dbProvider,
+            ChangeJson.Factory json,
+            RetryHelper retryHelper,
+            PatchSetUtil psUtil,
+            QtChangeUpdateOp.Factory qtUpdateFactory) {
+        super(retryHelper);
+        this.dbProvider = dbProvider;
+        this.json = json;
+        this.psUtil = psUtil;
+        this.qtUpdateFactory = qtUpdateFactory;
+    }
+
+    @Override
+    protected ChangeInfo applyImpl(BatchUpdate.Factory updateFactory,
+                                   ChangeResource rsrc,
+                                   AbandonInput input)
+                                   throws RestApiException, UpdateException,
+                                          OrmException, PermissionBackendException,
+                                          IOException {
+        Change change = rsrc.getChange();
+        logger.atInfo().log("qtcodereview: defer %s", rsrc.getChange().toString());
+
+        // Not allowed to defer if the current patch set is locked.
+        psUtil.checkPatchSetNotLocked(rsrc.getNotes());
+
+        // Defer uses same permission as abandon
+        rsrc.permissions().database(dbProvider).check(ChangePermission.ABANDON);
+
+        if (change.getStatus() != Change.Status.NEW && change.getStatus() != Change.Status.ABANDONED) {
+            logger.atSevere().log("qtcodereview: defer: change %s status wrong %s", change, change.getStatus());
+            throw new ResourceConflictException("change is " + ChangeUtil.status(change));
+        }
+
+        QtChangeUpdateOp op = qtUpdateFactory.create(Change.Status.DEFERRED, "Deferred", input.message, null);
+        try (BatchUpdate u =  updateFactory.create(dbProvider.get(), change.getProject(), rsrc.getUser(), TimeUtil.nowTs())) {
+            u.addOp(rsrc.getId(), op).execute();
+        }
+
+        change = op.getChange();
+        logger.atInfo().log("qtcodereview: deferred %s", change);
+
+        return json.noOptions().format(change);
+    }
+
+    @Override
+    public UiAction.Description getDescription(ChangeResource rsrc) {
+        UiAction.Description description = new UiAction.Description()
+                                                       .setLabel("Defer")
+                                                       .setTitle("Defer the change")
+                                                       .setVisible(false);
+
+        Change change = rsrc.getChange();
+        if (change.getStatus() != Change.Status.NEW && change.getStatus() != Change.Status.ABANDONED) {
+            return description;
+        }
+
+        try {
+            if (psUtil.isPatchSetLocked(rsrc.getNotes())) {
+                return description;
+            }
+        } catch (OrmException | IOException e) {
+            logger.atSevere().withCause(e).log("Failed to check if the current patch set of change %s is locked", change.getId());
+            return description;
+        }
+
+        return description.setVisible(rsrc.permissions().testOrFalse(ChangePermission.ABANDON));
+    }
+
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtModule.java b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtModule.java
index 5cfba4a..0753356 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtModule.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/qtcodereview/QtModule.java
@@ -4,6 +4,8 @@
 
 package com.googlesource.gerrit.plugins.qtcodereview;
 
+import static com.google.gerrit.server.change.ChangeResource.CHANGE_KIND;
+
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.extensions.config.FactoryModule;
 import com.google.gerrit.extensions.restapi.RestApiModule;
@@ -18,10 +20,13 @@ public class QtModule extends FactoryModule  {
     @Override
     protected void configure() {
 
+        factory(QtChangeUpdateOp.Factory.class);
+
         install(
             new RestApiModule() {
                 @Override
                 protected void configure() {
+                    post(CHANGE_KIND, "defer").to(QtDefer.class);
                 }
             }
         );
diff --git a/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtCodeReviewIT.java b/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtCodeReviewIT.java
index 2aa798a..fd0d42a 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtCodeReviewIT.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtCodeReviewIT.java
@@ -2,24 +2,72 @@
 
 package com.googlesource.gerrit.plugins.qtcodereview;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.acceptance.TestPlugin;
-import com.google.gerrit.acceptance.UseSsh;
+
+import com.google.gerrit.reviewdb.client.Change;
+
+import org.eclipse.jgit.revwalk.RevCommit;
 
 import org.junit.Test;
 
+
 @TestPlugin(
     name = "gerrit-plugin-qt-workflow",
     sysModule = "com.googlesource.gerrit.plugins.qtcodereview.QtModule",
     sshModule = "com.googlesource.gerrit.plugins.qtcodereview.QtSshModule"
 )
 
-@UseSsh
 public class QtCodeReviewIT extends LightweightPluginDaemonTest {
 
+    protected static final String R_HEADS = "refs/heads/";
+    protected static final String R_STAGING = "refs/staging/";
+    protected static final String R_PUSH = "refs/for/";
+
     @Test
     public void dummyTest() {
 
     }
 
+
+// Helper functions
+
+    protected void QtDefer(PushOneCommit.Result c) throws Exception {
+        RestResponse response = call_REST_API_Defer(c.getChangeId());
+        response.assertOK();
+    }
+
+    protected RestResponse call_REST_API_Defer(String changeId) throws Exception {
+        String url = "/changes/"+changeId+"/gerrit-plugin-qt-workflow~defer";
+        RestResponse response = userRestSession.post(url);
+        return response;
+    }
+
+    protected PushOneCommit.Result pushCommit(String branch,
+                                             String message,
+                                             String file,
+                                             String content)
+                                             throws Exception {
+        String pushRef = R_PUSH + branch;
+        PushOneCommit.Result c = createUserChange(pushRef, message, file, content);
+        Change change = c.getChange().change();
+        assertThat(change.getStatus()).isEqualTo(Change.Status.NEW);
+        return c;
+    }
+
+    protected PushOneCommit.Result createUserChange(String ref, String message, String file, String content) throws Exception {
+        PushOneCommit push = pushFactory.create(db, user.getIdent(), testRepo, message, file, content);
+        PushOneCommit.Result result = push.to(ref);
+        result.assertOkStatus();
+        return result;
+    }
+
+    protected void assertRefUpdatedEvents(String refName, RevCommit ... expected) throws Exception {
+        eventRecorder.assertRefUpdatedEvents(project.get(), refName, expected);
+    }
+
 }
diff --git a/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtDeferIT.java b/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtDeferIT.java
new file mode 100644
index 0000000..b2b46b8
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/qtcodereview/QtDeferIT.java
@@ -0,0 +1,124 @@
+// Copyright (C) 2018 The Qt Company
+
+package com.googlesource.gerrit.plugins.qtcodereview;
+
+import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.RestResponse;
+import com.google.gerrit.acceptance.TestPlugin;
+import com.google.gerrit.acceptance.UseSsh;
+
+import com.google.gerrit.common.data.Permission;
+import com.google.gerrit.extensions.api.changes.AbandonInput;
+import com.google.gerrit.reviewdb.client.Change;
+
+import org.eclipse.jgit.revwalk.RevCommit;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.apache.http.HttpStatus;
+
+@TestPlugin(
+    name = "gerrit-plugin-qt-workflow",
+    sysModule = "com.googlesource.gerrit.plugins.qtcodereview.QtModule",
+    sshModule = "com.googlesource.gerrit.plugins.qtcodereview.QtSshModule"
+)
+
+@UseSsh
+public class QtDeferIT extends QtCodeReviewIT {
+
+    @Before
+    public void SetDefaultPermissions() throws Exception {
+        grant(project, "refs/heads/master", Permission.ABANDON, false, REGISTERED_USERS);
+    }
+
+    @Test
+    public void singleChange_Defer() throws Exception {
+        RevCommit initialHead = getRemoteHead();
+        PushOneCommit.Result c = pushCommit("master", "commitmsg1","file1", "content1");
+
+        RevCommit updatedHead = qtDefer(c, initialHead);
+    }
+
+    @Test
+    public void singleChange_Defer_With_Input_Message() throws Exception {
+        PushOneCommit.Result c = pushCommit("master", "commitmsg1","file1", "content1");
+        approve(c.getChangeId());
+        String changeId = c.getChangeId();
+
+        AbandonInput abandonInput = new AbandonInput();
+        abandonInput.message = "myabandonednote";
+
+        String url = "/changes/"+changeId+"/gerrit-plugin-qt-workflow~defer";
+        RestResponse response = userRestSession.post(url, abandonInput);
+        response.assertOK();
+        Change change = c.getChange().change();
+        assertThat(change.getStatus()).isEqualTo(Change.Status.DEFERRED);
+    }
+
+    @Test
+    public void errorDefer_No_Permission() throws Exception {
+        deny(project, "refs/heads/master", Permission.ABANDON, REGISTERED_USERS);
+
+        PushOneCommit.Result c = pushCommit("master", "commitmsg1", "file1", "content1");
+        RestResponse response = qtDeferExpectFail(c, HttpStatus.SC_FORBIDDEN);
+        assertThat(response.getEntityContent()).isEqualTo("abandon not permitted");
+
+        grant(project, "refs/heads/master", Permission.ABANDON, false, REGISTERED_USERS);
+    }
+
+    @Test
+    public void errorDefer_Wrong_Status() throws Exception {
+        RevCommit initialHead = getRemoteHead();
+        PushOneCommit.Result c = pushCommit("master", "commitmsg1", "file1", "content1");
+        merge(c);
+
+        RestResponse response = qtDeferExpectFail(c, HttpStatus.SC_CONFLICT);
+        assertThat(response.getEntityContent()).isEqualTo("change is merged");
+    }
+
+
+    private RevCommit qtDefer(PushOneCommit.Result c,
+                              RevCommit initialHead)
+                              throws Exception {
+        String masterRef = R_HEADS + "master";
+        String stagingRef = R_STAGING + "master";
+
+        RestResponse response = call_REST_API_Defer(c.getChangeId());
+        response.assertOK();
+
+        RevCommit masterHead = getRemoteHead(project, masterRef);
+        assertThat(masterHead.getId()).isEqualTo(initialHead.getId()); // master is not updated
+
+        RevCommit stagingHead = getRemoteHead(project, stagingRef);
+        if (stagingHead != null) assertThat(stagingHead.getId()).isEqualTo(initialHead.getId()); // staging is not updated
+
+        assertRefUpdatedEvents(masterRef);   // no events
+        assertRefUpdatedEvents(stagingRef); // no events
+
+        Change change = c.getChange().change();
+        assertThat(change.getStatus()).isEqualTo(Change.Status.DEFERRED);
+
+        return masterHead;
+    }
+
+    private RestResponse qtDeferExpectFail(PushOneCommit.Result c,
+                                           int expectedStatus)
+                                           throws Exception {
+        RestResponse response = call_REST_API_Defer(c.getChangeId());
+        response.assertStatus(expectedStatus);
+
+        Change change = c.getChange().change();
+        assertThat(change.getStatus()).isNotEqualTo(Change.Status.DEFERRED);
+
+        return response;
+    }
+
+
+
+}