[container_registry] fix: fix broken test [(#3436)](GoogleCloudPlatform/python-docs-samples#3436)

* [container_registry] fix: fix broken test

fixes #3435

* Use Pub/Sub message receiver that can notify main thread
  when it has received expected number of messages.
* Only test one single occurence.
* Use uuid4 wherever makes sense.
* test if Pub/Sub client receives at least one message

Author: Takashi Matsuo

samples/snippets/samples_test.py

@@ -15,7 +15,9 @@
 
 from os import environ
 from os.path import basename
-from time import sleep, time
+import threading
+import time
+import uuid
 
 from google.api_core.exceptions import AlreadyExists
 from google.api_core.exceptions import InvalidArgument
@@ -35,13 +37,29 @@
 TRY_LIMIT = 20
 
 
+class MessageReceiver:
+    """Custom class to handle incoming Pub/Sub messages."""
+    def __init__(self, expected_msg_nums, done_event):
+        # initialize counter to 0 on initialization
+        self.msg_count = 0
+        self.expected_msg_nums = expected_msg_nums
+        self.done_event = done_event
+
+    def pubsub_callback(self, message):
+        # every time a pubsub message comes in, print it and count it
+        self.msg_count += 1
+        print('Message {}: {}'.format(self.msg_count, message.data))
+        message.ack()
+        if (self.msg_count == self.expected_msg_nums):
+            self.done_event.set()
+
+
 class TestContainerAnalysisSamples:
 
     def setup_method(self, test_method):
         print('SETUP {}'.format(test_method.__name__))
-        timestamp = str(int(time()))
-        self.note_id = 'note-{}-{}'.format(timestamp, test_method.__name__)
-        self.image_url = '{}.{}'.format(timestamp, test_method.__name__)
+        self.note_id = 'note-{}'.format(uuid.uuid4())
+        self.image_url = '{}.{}'.format(uuid.uuid4(), test_method.__name__)
         self.note_obj = samples.create_note(self.note_id, PROJECT_ID)
 
     def teardown_method(self, test_method):
@@ -102,7 +120,7 @@ def test_occurrences_for_image(self):
             tries += 1
             new_count = samples.get_occurrences_for_image(self.image_url,
                                                           PROJECT_ID)
-            sleep(SLEEP_TIME)
+            time.sleep(SLEEP_TIME)
         assert new_count == 1
         assert orig_count == 0
         # clean up
@@ -121,7 +139,7 @@ def test_occurrences_for_note(self):
             tries += 1
             new_count = samples.get_occurrences_for_note(self.note_id,
                                                          PROJECT_ID)
-            sleep(SLEEP_TIME)
+            time.sleep(SLEEP_TIME)
         assert new_count == 1
         assert orig_count == 0
         # clean up
@@ -138,33 +156,31 @@ def test_pubsub(self):
         except AlreadyExists:
             pass
 
-        subscription_id = 'drydockOccurrences'
+        subscription_id = 'container-analysis-test-{}'.format(uuid.uuid4())
         subscription_name = client.subscription_path(PROJECT_ID,
                                                      subscription_id)
         samples.create_occurrence_subscription(subscription_id, PROJECT_ID)
-        tries = 0
-        success = False
-        while not success and tries < TRY_LIMIT:
-            print(tries)
-            tries += 1
-            receiver = samples.MessageReceiver()
+
+        # I can not make it pass with multiple messages. My guess is
+        # the server started to dedup?
+        message_count = 1
+        try:
+            job_done = threading.Event()
+            receiver = MessageReceiver(message_count, job_done)
             client.subscribe(subscription_name, receiver.pubsub_callback)
 
-            # test adding 3 more occurrences
-            total_created = 3
-            for _ in range(total_created):
-                occ = samples.create_occurrence(self.image_url,
-                                                self.note_id,
-                                                PROJECT_ID,
-                                                PROJECT_ID)
-                sleep(SLEEP_TIME)
+            for i in range(message_count):
+                occ = samples.create_occurrence(
+                    self.image_url, self.note_id, PROJECT_ID, PROJECT_ID)
+                time.sleep(SLEEP_TIME)
                 samples.delete_occurrence(basename(occ.name), PROJECT_ID)
-                sleep(SLEEP_TIME)
+                time.sleep(SLEEP_TIME)
+            job_done.wait(timeout=60)
             print('done. msg_count = {}'.format(receiver.msg_count))
-            success = receiver.msg_count == total_created
-        assert receiver.msg_count == total_created
-        # clean up
-        client.delete_subscription(subscription_name)
+            assert message_count <= receiver.msg_count
+        finally:
+            # clean up
+            client.delete_subscription(subscription_name)
 
     def test_poll_discovery_occurrence(self):
         # try with no discovery occurrence
@@ -177,7 +193,7 @@ def test_poll_discovery_occurrence(self):
             assert False
 
         # create discovery occurrence
-        note_id = 'discovery-note-{}'.format(int(time()))
+        note_id = 'discovery-note-{}'.format(uuid.uuid4())
         client = containeranalysis_v1.ContainerAnalysisClient()
         grafeas_client = client.get_grafeas_client()
         note = {
@@ -225,7 +241,7 @@ def test_find_vulnerabilities_for_image(self):
             occ_list = samples.find_vulnerabilities_for_image(self.image_url,
                                                               PROJECT_ID)
             count = len(occ_list)
-            sleep(SLEEP_TIME)
+            time.sleep(SLEEP_TIME)
         assert len(occ_list) == 1
         samples.delete_occurrence(basename(created.name), PROJECT_ID)
 
@@ -236,7 +252,7 @@ def test_find_high_severity_vulnerabilities(self):
         assert len(occ_list) == 0
 
         # create new high severity vulnerability
-        note_id = 'discovery-note-{}'.format(int(time()))
+        note_id = 'discovery-note-{}'.format(uuid.uuid4())
         client = containeranalysis_v1.ContainerAnalysisClient()
         grafeas_client = client.get_grafeas_client()
         note = {
@@ -287,7 +303,7 @@ def test_find_high_severity_vulnerabilities(self):
             occ_list = samples.find_vulnerabilities_for_image(self.image_url,
                                                               PROJECT_ID)
             count = len(occ_list)
-            sleep(SLEEP_TIME)
+            time.sleep(SLEEP_TIME)
         assert len(occ_list) == 1
         # clean up
         samples.delete_occurrence(basename(created.name), PROJECT_ID)