Fix metric-statistics doesn't respond "Bad Request"

When metric-statistics with end_time equals start_time received,
python monasca-api responds "200 OK" instead of "400 Bad Request".

Change-Id: I56cf42c2530be83b4555a05b4c433666a4ccdb5e
Closes-Bug: #1520029

monasca_api/tests/test_validation.py

@@ -134,3 +134,40 @@ class TestRoleValidation(unittest.TestCase):
         self.assertRaises(
             falcon.HTTPUnauthorized,
             helpers.validate_authorization, req, authorized_roles)
+
+
+class TestTimestampsValidation(unittest.TestCase):
+
+    def test_valid_timestamps(self):
+        start_time = '2015-01-01T00:00:00Z'
+        end_time = '2015-01-01T00:00:01Z'
+        start_timestamp = helpers._convert_time_string(start_time)
+        end_timestamp = helpers._convert_time_string(end_time)
+
+        try:
+            helpers.validate_start_end_timestamps(start_timestamp,
+                                                  end_timestamp)
+        except:
+            self.fail("shouldn't happen")
+
+    def test_same_timestamps(self):
+        start_time = '2015-01-01T00:00:00Z'
+        end_time = start_time
+        start_timestamp = helpers._convert_time_string(start_time)
+        end_timestamp = helpers._convert_time_string(end_time)
+
+        self.assertRaises(
+            falcon.HTTPBadRequest,
+            helpers.validate_start_end_timestamps,
+            start_timestamp, end_timestamp)
+
+    def test_end_before_than_start(self):
+        start_time = '2015-01-01T00:00:00Z'
+        end_time = '2014-12-31T23:59:59Z'
+        start_timestamp = helpers._convert_time_string(start_time)
+        end_timestamp = helpers._convert_time_string(end_time)
+
+        self.assertRaises(
+            falcon.HTTPBadRequest,
+            helpers.validate_start_end_timestamps,
+            start_timestamp, end_timestamp)

monasca_api/v2/reference/helpers.py

@@ -222,6 +222,13 @@ def get_query_endtime_timestamp(req, required=True):
         raise HTTPUnprocessableEntityError('Unprocessable Entity', ex.message)
 
 
+def validate_start_end_timestamps(start_timestamp, end_timestamp=None):
+    if end_timestamp:
+        if not start_timestamp < end_timestamp:
+            raise falcon.HTTPBadRequest('Bad request',
+                                        'start_time must be before end_time')
+
+
 def _convert_time_string(date_time_string):
     dt = timeutils.parse_isotime(date_time_string)
     dt = dt.replace(tzinfo=None)

monasca_api/v2/reference/metrics.py

@@ -168,6 +168,7 @@ class MetricsMeasurements(metrics_api_v2.MetricsMeasurementsV2API):
         helpers.validate_query_dimensions(dimensions)
         start_timestamp = helpers.get_query_starttime_timestamp(req)
         end_timestamp = helpers.get_query_endtime_timestamp(req, False)
+        helpers.validate_start_end_timestamps(start_timestamp, end_timestamp)
         offset = helpers.get_query_param(req, 'offset')
         limit = helpers.get_limit(req)
         merge_metrics_flag = get_merge_metrics_flag(req)
@@ -222,6 +223,7 @@ class MetricsStatistics(metrics_api_v2.MetricsStatisticsV2API):
         helpers.validate_query_dimensions(dimensions)
         start_timestamp = helpers.get_query_starttime_timestamp(req)
         end_timestamp = helpers.get_query_endtime_timestamp(req, False)
+        helpers.validate_start_end_timestamps(start_timestamp, end_timestamp)
         statistics = helpers.get_query_statistics(req)
         period = helpers.get_query_period(req)
         offset = helpers.get_query_param(req, 'offset')

monasca_tempest_tests/tests/api/test_measurements.py

@@ -184,6 +184,16 @@ class TestMeasurements(base.BaseMonascaTest):
         self._verify_list_measurements_meas_len(measurements=measurements,
                                                 test_len=NUM_MEASUREMENTS)
 
+    @test.attr(type="gate")
+    @test.attr(type=['negative'])
+    def test_list_measurements_with_endtime_equals_starttime(self):
+        query_parms = '?name=' + str(self._names_list[0]) + \
+                      '&merge_metrics=true' \
+                      '&start_time=' + str(self._start_time) + \
+                      '&end_time=' + str(self._start_time)
+        self.assertRaises(exceptions.BadRequest,
+                          self.monasca_client.list_measurements, query_parms)
+
     @test.attr(type="gate")
     def test_list_measurements_with_offset_limit(self):
         query_parms = '?name=' + str(self._names_list[1]) + \