Add a test for dequeue-on-new-patchest

This setting (which is likely rarely used) instructs Zuul not to
dequeue an item merely because it has had a new patchset uploaded.

However, if another item depends on such a change, that other item
should still be dequeued because its dependencies are out of date.
Add a test for that so that future changes to the change cache don't
inadvertently alter this behavior.

Change-Id: Ib2e8504c37644e06d0ac0608fa7c56d092e2673d

tests/fixtures/layouts/no-dequeue-on-new-patchset.yaml

@@ -0,0 +1,49 @@
+- pipeline:
+    name: check
+    manager: independent
+    dequeue-on-new-patchset: false
+    trigger:
+      gerrit:
+        - event: patchset-created
+    require:
+      gerrit:
+        approval:
+          - Code-Review: 2
+    success:
+      gerrit:
+        Verified: 1
+    failure:
+      gerrit:
+        Verified: -1
+
+- job:
+    name: base
+    parent: null
+    run: playbooks/base.yaml
+
+- job:
+    name: project1-test
+
+- job:
+    name: project2-test
+
+- job:
+    name: project3-test
+
+- project:
+    name: org/project1
+    check:
+      jobs:
+        - project1-test
+
+- project:
+    name: org/project2
+    check:
+      jobs:
+        - project2-test
+
+- project:
+    name: org/project3
+    check:
+      jobs:
+        - project3-test

tests/unit/test_scheduler.py

@@ -2690,6 +2690,65 @@ class TestScheduler(ZuulTestCase):
         self.assertEqual(D.reported, 2)
         self.assertEqual(len(self.history), 9)  # 3 each for A, B, D.
 
+    @simple_layout('layouts/no-dequeue-on-new-patchset.yaml')
+    def test_no_dequeue_on_new_patchset(self):
+        "Test the dequeue-on-new-patchset false value"
+        A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
+        self.executor_server.hold_jobs_in_build = True
+        A.addApproval('Code-Review', 2)
+
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 1)
+
+        A.addPatchset()
+        A.addApproval('Code-Review', 2)
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(2))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 2)
+
+        self.executor_server.hold_jobs_in_build = False
+        self.executor_server.release()
+        self.waitUntilSettled()
+
+        self.assertHistory([
+            dict(name='project1-test', result='SUCCESS', changes='1,1'),
+            dict(name='project1-test', result='SUCCESS', changes='1,2'),
+        ], ordered=False)
+
+    @simple_layout('layouts/no-dequeue-on-new-patchset.yaml')
+    def test_no_dequeue_on_new_patchset_deps(self):
+        "Test dependencies are updated if dequeue-on-new-patchset is false"
+        A = self.fake_gerrit.addFakeChange('org/project1', 'master', 'A')
+        B = self.fake_gerrit.addFakeChange('org/project1', 'master', 'B')
+        B.data['commitMessage'] = '%s\n\nDepends-On: %s\n' % (
+            B.subject, A.data['url'])
+        B.addApproval('Code-Review', 2)
+
+        self.executor_server.hold_jobs_in_build = True
+
+        self.fake_gerrit.addEvent(B.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 1)
+
+        A.addPatchset()
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(2))
+        self.waitUntilSettled()
+
+        self.assertEqual(len(self.builds), 0)
+
+        self.executor_server.hold_jobs_in_build = False
+        self.executor_server.release()
+        self.waitUntilSettled()
+
+        # The item should be dequeued because of the dependency change
+        self.assertHistory([
+            dict(name='project1-test', result='ABORTED', changes='1,1 2,1'),
+        ], ordered=False)
+
     def test_new_patchset_check(self):
         "Test a new patchset in check"