Update the list of rejected jobs if match function is used

The jobs that are being pruned by the `match` function should be added
to the list of rejected jobs, otherwise the metadata generated at the
end of a test run is incorrect.

Because the list of rejected jobs is initially empty but can be altered
in several places (`run_alternate_selection()` and
`finish_bootstrap()`), it is updated in these functions instead of being
replaced by another list.

The metadata that states if a test plan has been modified
(`custom_joblist`) should also be set to True in these cases.

Fix #1568

checkbox-ng/plainbox/impl/session/assistant.py

@@ -946,7 +946,7 @@ def finish_bootstrap(self):
         if self._match_qualifiers:
             # when `match` is provided, use the test plan but prune it to
             # only pull the jobs asked in the launcher or their dependencies
-            desired_job_list = select_units(
+            desired_matching_job_list = select_units(
                 desired_job_list,
                 self._match_qualifiers
                 + self._exclude_qualifiers
@@ -956,6 +956,16 @@ def finish_bootstrap(self):
                     )
                 ],
             )
+            rejected_job_list = [
+                job.id
+                for job in desired_job_list
+                if job not in desired_matching_job_list
+            ]
+            if rejected_job_list:
+                for rejected_job in rejected_job_list:
+                    self._metadata.rejected_jobs.append(rejected_job)
+                self._metadata.custom_joblist = True
+            desired_job_list = desired_matching_job_list
 
         self._context.state.update_desired_job_list(desired_job_list)
         # Set subsequent usage expectations i.e. all of the runtime parts are
@@ -997,13 +1007,11 @@ def use_alternate_selection(self, selection: "Iterable[str]"):
         UsageExpectation.of(self).enforce()
         self._metadata.custom_joblist = True
         desired_job_list = []
-        rejected_job_list = []
         for job_id in self.get_static_todo_list():
             if job_id in selection:
                 desired_job_list.append(self._context.get_unit(job_id, "job"))
             else:
-                rejected_job_list.append(job_id)
-        self._metadata.rejected_jobs = rejected_job_list
+                self._metadata.rejected_jobs.append(job_id)
         self._context.state.update_desired_job_list(desired_job_list)
 
     @raises(UnexpectedMethodCall)

checkbox-ng/plainbox/impl/session/test_assistant.py

@@ -278,6 +278,33 @@ def test_finish_bootstrap_match_no_match(
         # and another time to prune it for match
         self.assertEqual(select_units_mock.call_count, 1)
 
+    @mock.patch("plainbox.impl.session.assistant.UsageExpectation")
+    @mock.patch("plainbox.impl.session.assistant.select_units")
+    def test_finish_bootstrap_match_rejected_jobs(
+        self, select_units_mock, ue_mock, get_providers_mock
+    ):
+        self_mock = mock.MagicMock()
+        self_mock._metadata.rejected_jobs = []
+        # this is just to test that the subfunction is called if this arr is
+        # defined, assumes the select_units function is mocked
+        self_mock._match_qualifiers = [1, 2, 3]
+
+        job1_id = "com.canonical.certification::job_1"
+        job2_id = "com.canonical.certification::job_2"
+        job1 = JobDefinition({"id": job1_id})
+        job2 = JobDefinition({"id": job2_id})
+        select_units_mock.side_effect = [[job1, job2], [job2]]
+
+        SessionAssistant.finish_bootstrap(self_mock)
+
+        # called once to get all the jobs for the selected testplan
+        # and another time to prune it for match`
+        self.assertEqual(select_units_mock.call_count, 2)
+
+        # job1 is rejected, so the metadata is updated accordingly
+        self.assertEqual(self_mock._metadata.rejected_jobs, [job1_id])
+        self.assertTrue(self_mock._metadata.custom_joblist)
+
     @mock.patch(
         "plainbox.impl.session.assistant.UsageExpectation",
         new=mock.MagicMock(),
@@ -290,12 +317,13 @@ def test_use_alternate_selection(self, mock_get_providers):
         job1 = JobDefinition({"id": job1_id})
         job2 = JobDefinition({"id": job2_id})
 
+        self_mock._metadata.rejected_jobs = ["already-rejected-job"]
         self_mock.get_static_todo_list.return_value = [job1_id, job2_id]
         self_mock._context.get_unit.side_effect = [job1, job2]
         selection = [job1_id]
 
         SessionAssistant.use_alternate_selection(self_mock, selection)
-        self.assertEqual(len(self_mock._metadata.rejected_jobs), 1)
+        self.assertEqual(len(self_mock._metadata.rejected_jobs), 2)
         self_mock._context.state.update_desired_job_list.assert_called_with(
             [job1]
         )