DistributionAggregation fixes (#375)

Fix a few existing bugs in DistributionAggregation, and lint/formatting issues
in related files.

opencensus/stats/aggregation.py

@@ -133,7 +133,7 @@ def __init__(
         self._boundaries = bucket_boundaries.BucketBoundaries(boundaries)
         self._distribution = distribution or {}
         self.aggregation_data = aggregation_data.DistributionAggregationData(
-            0, 0, 0, 0, 0, None, boundaries)
+            0, 0, float('inf'), float('-inf'), 0, None, boundaries)
 
     @property
     def boundaries(self):

opencensus/stats/aggregation_data.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
 from opencensus.stats import bucket_boundaries
 
 
@@ -21,6 +22,7 @@ class BaseAggregationData(object):
     :param aggregation_data: represents the aggregated value from a collection
 
     """
+
     def __init__(self, aggregation_data):
         self._aggregation_data = aggregation_data
 
@@ -37,6 +39,7 @@ class SumAggregationDataFloat(BaseAggregationData):
     :param sum_data: represents the aggregated sum
 
     """
+
     def __init__(self, sum_data):
         super(SumAggregationDataFloat, self).__init__(sum_data)
         self._sum_data = sum_data
@@ -60,6 +63,7 @@ class CountAggregationData(BaseAggregationData):
     :param count_data: represents the aggregated count
 
     """
+
     def __init__(self, count_data):
         super(CountAggregationData, self).__init__(count_data)
         self._count_data = count_data
@@ -104,6 +108,7 @@ class DistributionAggregationData(BaseAggregationData):
     :param bounds: the histogram distribution of the values
 
     """
+
     def __init__(self,
                  mean_data,
                  count_data,
@@ -123,13 +128,14 @@ def __init__(self,
             bounds = []
 
         if counts_per_bucket is None:
-            counts_per_bucket = []
-            bucket_size = len(bounds) + 1
-            for i in range(bucket_size):
-                counts_per_bucket.append(0)
+            counts_per_bucket = [0 for ii in range(len(bounds) + 1)]
+        elif len(counts_per_bucket) != len(bounds) + 1:
+            raise ValueError("counts_per_bucket length does not match bounds "
+                             "length")
+
         self._counts_per_bucket = counts_per_bucket
         self._bounds = bucket_boundaries.BucketBoundaries(
-                                            boundaries=bounds).boundaries
+            boundaries=bounds).boundaries
         bucket = 0
         for _ in self.bounds:
             bucket = bucket + 1
@@ -207,30 +213,24 @@ def add_sample(self, value, timestamp, attachments):
 
         old_mean = self._mean_data
         self._mean_data = self._mean_data + (
-                          (value - self._mean_data) / self._count_data)
+            (value - self._mean_data) / self._count_data)
         self._sum_of_sqd_deviations = self._sum_of_sqd_deviations + (
-                                      (value - old_mean) *
-                                      (value - self._mean_data))
+            (value - old_mean) * (value - self._mean_data))
 
     def increment_bucket_count(self, value):
         """Increment the bucket count based on a given value from the user"""
-        i = 0
-        incremented = False
-        for b in self._bounds:
-            if value < b and not incremented:
-                self._counts_per_bucket[i] += 1
-                incremented = True
-            i += 1
-
-        if incremented:
-            return i
-
         if len(self._bounds) == 0:
             self._counts_per_bucket[0] += 1
-            return i
+            return 0
 
-        self._counts_per_bucket[(len(self._bounds))-1] += 1
-        return i
+        for ii, bb in enumerate(self._bounds):
+            if value < bb:
+                self._counts_per_bucket[ii] += 1
+                return ii
+        else:
+            last_bucket_index = len(self._bounds)
+            self._counts_per_bucket[last_bucket_index] += 1
+            return last_bucket_index
 
 
 class LastValueAggregationData(BaseAggregationData):
@@ -241,6 +241,7 @@ class LastValueAggregationData(BaseAggregationData):
     :param value: represents the current value
 
     """
+
     def __init__(self, value):
         super(LastValueAggregationData, self).__init__(value)
         self._value = value
@@ -271,10 +272,7 @@ class Exemplar(object):
         :param attachments: the contextual information about the example value.
     """
 
-    def __init__(self,
-                 value,
-                 timestamp,
-                 attachments):
+    def __init__(self, value, timestamp, attachments):
         self._value = value
 
         self._timestamp = timestamp

tests/unit/stats/test_aggregation.py

@@ -12,92 +12,113 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from datetime import datetime
 import unittest
-import mock
+
 from opencensus.stats import aggregation as aggregation_module
 
 
 class TestBaseAggregation(unittest.TestCase):
-
     def test_constructor_defaults(self):
         base_aggregation = aggregation_module.BaseAggregation()
 
-        self.assertEqual(aggregation_module.Type.NONE, base_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.NONE,
+                         base_aggregation.aggregation_type)
         self.assertEqual([], base_aggregation.buckets)
 
     def test_constructor_explicit(self):
 
         buckets = ["test"]
         base_aggregation = aggregation_module.BaseAggregation(buckets=buckets)
 
-        self.assertEqual(aggregation_module.Type.NONE, base_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.NONE,
+                         base_aggregation.aggregation_type)
         self.assertEqual(["test"], base_aggregation.buckets)
 
 
 class TestSumAggregation(unittest.TestCase):
-
     def test_constructor_defaults(self):
         sum_aggregation = aggregation_module.SumAggregation()
 
         self.assertEqual(0, sum_aggregation.sum.sum_data)
-        self.assertEqual(aggregation_module.Type.SUM, sum_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.SUM,
+                         sum_aggregation.aggregation_type)
 
     def test_constructor_explicit(self):
         sum = 1
 
         sum_aggregation = aggregation_module.SumAggregation(sum=sum)
 
         self.assertEqual(1, sum_aggregation.sum.sum_data)
-        self.assertEqual(aggregation_module.Type.SUM, sum_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.SUM,
+                         sum_aggregation.aggregation_type)
 
 
 class TestCountAggregation(unittest.TestCase):
-
     def test_constructor_defaults(self):
         count_aggregation = aggregation_module.CountAggregation()
 
         self.assertEqual(0, count_aggregation.count.count_data)
-        self.assertEqual(aggregation_module.Type.COUNT, count_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.COUNT,
+                         count_aggregation.aggregation_type)
 
     def test_constructor_explicit(self):
         count = 4
 
         count_aggregation = aggregation_module.CountAggregation(count=count)
 
         self.assertEqual(4, count_aggregation.count.count_data)
-        self.assertEqual(aggregation_module.Type.COUNT, count_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.COUNT,
+                         count_aggregation.aggregation_type)
 
 
 class TestLastValueAggregation(unittest.TestCase):
-
     def test_constructor_defaults(self):
         last_value_aggregation = aggregation_module.LastValueAggregation()
 
         self.assertEqual(0, last_value_aggregation.value)
-        self.assertEqual(aggregation_module.Type.LASTVALUE, last_value_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.LASTVALUE,
+                         last_value_aggregation.aggregation_type)
 
     def test_constructor_explicit(self):
         val = 16
-        last_value_aggregation = aggregation_module.LastValueAggregation(value=val)
+        last_value_aggregation = aggregation_module.LastValueAggregation(
+            value=val)
 
         self.assertEqual(16, last_value_aggregation.value)
-        self.assertEqual(aggregation_module.Type.LASTVALUE, last_value_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.LASTVALUE,
+                         last_value_aggregation.aggregation_type)
 
 
 class TestDistributionAggregation(unittest.TestCase):
-
     def test_constructor_defaults(self):
         distribution_aggregation = aggregation_module.DistributionAggregation()
 
         self.assertEqual([], distribution_aggregation.boundaries.boundaries)
         self.assertEqual({}, distribution_aggregation.distribution)
-        self.assertEqual(aggregation_module.Type.DISTRIBUTION, distribution_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.DISTRIBUTION,
+                         distribution_aggregation.aggregation_type)
 
     def test_constructor_explicit(self):
         boundaries = ["test"]
         distribution = {1: "test"}
-        distribution_aggregation = aggregation_module.DistributionAggregation(boundaries=boundaries, distribution=distribution)
+        distribution_aggregation = aggregation_module.DistributionAggregation(
+            boundaries=boundaries, distribution=distribution)
 
-        self.assertEqual(["test"], distribution_aggregation.boundaries.boundaries)
+        self.assertEqual(["test"],
+                         distribution_aggregation.boundaries.boundaries)
         self.assertEqual({1: "test"}, distribution_aggregation.distribution)
-        self.assertEqual(aggregation_module.Type.DISTRIBUTION, distribution_aggregation.aggregation_type)
+        self.assertEqual(aggregation_module.Type.DISTRIBUTION,
+                         distribution_aggregation.aggregation_type)
+
+    def test_min_max(self):
+        da = aggregation_module.DistributionAggregation([])
+
+        self.assertEqual(da.aggregation_data.min, float('inf'))
+        self.assertEqual(da.aggregation_data.max, float('-inf'))
+
+        for dp in range(-10, 11):
+            da.aggregation_data.add_sample(dp, datetime(1999, 12, 31), {})
+
+        self.assertEqual(da.aggregation_data.min, -10)
+        self.assertEqual(da.aggregation_data.max, 10)