test: Modify testRestRateLimit test to report when system is too slow.

Add an explicit check on the runtime and an error message that reports
that the runtime was exceeded for the test to complete as written.

testRestRateLimit requires that it finish within 3 seconds. Otherwise
the number of remaining requests in the rate limit does not decrease
on every call. If disk I/O is high, the anydbm version of this test
can take > 3 seconds and result in a failed test.

My other alternative was to measure the runtime and adjust the test to
match the values that are returned. This seems like too much work and
is unlikely to be an issue outside of a developers under powered
system.

Author: rouilj

test/rest_common.py

@@ -1076,8 +1076,12 @@ def testPagination(self):
 
     def testRestRateLimit(self):
 
-        self.db.config['WEB_API_CALLS_PER_INTERVAL'] = 20
-        self.db.config['WEB_API_INTERVAL_IN_SEC'] = 60
+        calls_per_interval = 20
+        interval_sec = 60
+        wait_time_str = str(int(interval_sec/calls_per_interval))
+
+        self.db.config['WEB_API_CALLS_PER_INTERVAL'] = calls_per_interval
+        self.db.config['WEB_API_INTERVAL_IN_SEC'] = interval_sec
 
         # Otk code never passes through the
         # retry loop. Not sure why but I can force it
@@ -1090,17 +1094,22 @@ def testRestRateLimit(self):
             # sqlite or anydbm. So don't need to exercise code.
             pass
 
-        print("Now realtime start:", datetime.utcnow())
+        start_time = datetime.utcnow()
         # don't set an accept header; json should be the default
         # use up all our allowed api calls
-        for i in range(20):
-            # i is 0 ... 19
+        for i in range(calls_per_interval):
+            # i is 0 ... calls_per_interval
             self.client_error_message = []
             self.server.client.env.update({'REQUEST_METHOD': 'GET'})
             results = self.server.dispatch('GET',
                             "/rest/data/user/%s/realname"%self.joeid,
                             self.empty_form)
 
+            loop_time = datetime.utcnow()
+            self.assertLess((loop_time-start_time).total_seconds(),
+                            int(wait_time_str),
+                    "Test system is too slow to complete test as configured")
+
             # is successful
             self.assertEqual(self.server.client.response_code, 200)
             # does not have Retry-After header as we have
@@ -1136,11 +1145,12 @@ def testRestRateLimit(self):
             59, delta=5)
         self.assertEqual(
             str(self.server.client.additional_headers["Retry-After"]),
-            "3")  # check as string
+            wait_time_str)  # check as string
 
         print("Reset:", self.server.client.additional_headers["X-RateLimit-Reset"])
         print("Now realtime pre-sleep:", datetime.utcnow())
-        sleep(3.1) # sleep as requested so we can do another login
+        # sleep as requested so we can do another login
+        sleep(float(wait_time_str) + 0.1)
         print("Now realtime post-sleep:", datetime.utcnow())
 
         # this should succeed
@@ -1181,11 +1191,13 @@ def testRestRateLimit(self):
         self.assertEqual(self.server.client.response_code, 429)
         self.assertEqual(
             str(self.server.client.additional_headers["Retry-After"]),
-            "3")  # check as string
+            wait_time_str)  # check as string
 
         json_dict = json.loads(b2s(results))
-        self.assertEqual(json_dict['error']['msg'],
-                         "Api rate limits exceeded. Please wait: 3 seconds.")
+        self.assertEqual(
+            json_dict['error']['msg'],
+            "Api rate limits exceeded. Please wait: %s seconds." % 
+            wait_time_str)
 
         # reset rest params
         self.db.config['WEB_API_CALLS_PER_INTERVAL'] = 0