Add aggregation temporality conversion algorithm

Fixes open-telemetry#2329

opentelemetry-sdk/src/opentelemetry/sdk/_metrics/aggregation.py

@@ -12,9 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from dataclasses import replace
 from abc import ABC, abstractmethod
 from bisect import bisect_left
+from dataclasses import replace
 from logging import getLogger
 from math import inf
 from threading import Lock
@@ -242,12 +242,14 @@ def _convert_aggregation_temporality(
         )
 
         return Sum(
-            aggregation_temporality=aggregation_temporality,
-            is_monotonic=is_monotonic,
             start_time_unix_nano=previous_point.start_time_unix_nano,
             time_unix_nano=current_point.time_unix_nano,
             value=value,
+            aggregation_temporality=aggregation_temporality,
+            is_monotonic=is_monotonic,
         )
 
-    elif current_point_type is Gauge:
+    if current_point_type is Gauge:
         return current_point
+
+    return None

opentelemetry-sdk/tests/metrics/test_aggregation.py

@@ -18,19 +18,16 @@
 from unittest import TestCase
 
 from opentelemetry.sdk._metrics.aggregation import (
+    AggregationTemporality,
     AsynchronousSumAggregation,
     ExplicitBucketHistogramAggregation,
     LastValueAggregation,
     SynchronousSumAggregation,
+    _convert_aggregation_temporality,
     _InstrumentMonotonicityAwareAggregation,
-    _convert_aggregation_temporality
 )
-from opentelemetry.sdk._metrics.aggregation import AggregationTemporality
 from opentelemetry.sdk._metrics.measurement import Measurement
-from opentelemetry.sdk._metrics.point import (
-    Gauge,
-    Sum,
-)
+from opentelemetry.sdk._metrics.point import Gauge, Sum
 
 
 class TestSynchronousSumAggregation(TestCase):
@@ -326,18 +323,110 @@ def test_mismatched_point_types(self):
 
     def test_current_point_sum_previous_point_none(self):
 
-        point_arguments = (0, 0, 0, AggregationTemporality.DELTA, False)
+        current_point = Sum(0, 0, 0, AggregationTemporality.DELTA, False)
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                None, current_point, AggregationTemporality.CUMULATIVE
+            ),
+            replace(
+                current_point,
+                aggregation_temporality=AggregationTemporality.CUMULATIVE,
+            ),
+        )
+
+    def test_current_point_sum_current_point_same_aggregation_temporality(
+        self,
+    ):
 
-        current_point = Sum(*point_arguments)
+        current_point = Sum(0, 0, 0, AggregationTemporality.DELTA, False)
 
         self.assertEqual(
             _convert_aggregation_temporality(
-                None,
+                Sum(0, 0, 0, AggregationTemporality.DELTA, False),
                 current_point,
-                AggregationTemporality.CUMULATIVE
+                AggregationTemporality.DELTA,
             ),
-            replace(
+            current_point,
+        )
+
+        current_point = Sum(0, 0, 0, AggregationTemporality.CUMULATIVE, False)
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(0, 0, 0, AggregationTemporality.CUMULATIVE, False),
                 current_point,
-                aggregation_temporality=AggregationTemporality.CUMULATIVE
-            )
+                AggregationTemporality.CUMULATIVE,
+            ),
+            current_point,
+        )
+
+    def test_current_point_sum_aggregation_temporality_delta(self):
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.CUMULATIVE, False),
+                Sum(4, 5, 6, AggregationTemporality.CUMULATIVE, False),
+                AggregationTemporality.DELTA,
+            ),
+            Sum(1, 5, 3, AggregationTemporality.DELTA, False),
+        )
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.CUMULATIVE, True),
+                Sum(4, 5, 6, AggregationTemporality.CUMULATIVE, False),
+                AggregationTemporality.DELTA,
+            ),
+            Sum(1, 5, 3, AggregationTemporality.DELTA, False),
+        )
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.CUMULATIVE, True),
+                Sum(4, 5, 6, AggregationTemporality.CUMULATIVE, True),
+                AggregationTemporality.DELTA,
+            ),
+            Sum(1, 5, 3, AggregationTemporality.DELTA, True),
+        )
+
+    def test_current_point_sum_aggregation_temporality_cumulative(self):
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.DELTA, False),
+                Sum(4, 5, 6, AggregationTemporality.DELTA, False),
+                AggregationTemporality.CUMULATIVE,
+            ),
+            Sum(1, 5, 9, AggregationTemporality.CUMULATIVE, False),
+        )
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.DELTA, True),
+                Sum(4, 5, 6, AggregationTemporality.DELTA, False),
+                AggregationTemporality.CUMULATIVE,
+            ),
+            Sum(1, 5, 9, AggregationTemporality.CUMULATIVE, False),
+        )
+
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.DELTA, True),
+                Sum(4, 5, 6, AggregationTemporality.DELTA, True),
+                AggregationTemporality.CUMULATIVE,
+            ),
+            Sum(1, 5, 9, AggregationTemporality.CUMULATIVE, True),
+        )
+
+    def test_current_point_gauge(self):
+
+        current_point = (Gauge(0, 0),)
+        self.assertEqual(
+            _convert_aggregation_temporality(
+                Sum(1, 2, 3, AggregationTemporality.DELTA, True),
+                current_point,
+                AggregationTemporality.CUMULATIVE,
+            ),
+            current_point,
         )