Fix CollectorRegistry import and test assertion

Author: Manvi2402

exporter/opentelemetry-exporter-prometheus/src/opentelemetry/exporter/prometheus/__init__.py

@@ -69,7 +69,7 @@
 from os import environ
 from typing import Deque, Dict, Iterable, Sequence, Tuple, Union
 
-from prometheus_client import start_http_server
+from prometheus_client import CollectorRegistry, start_http_server
 from prometheus_client.core import (
     REGISTRY,
     CounterMetricFamily,

exporter/opentelemetry-exporter-prometheus/tests/test_prometheus_exporter.py

@@ -56,13 +56,16 @@ def setUp(self):
         )
 
     def test_custom_registry(self):
-        custom_registry = CollectorRegistry()
-        reader = PrometheusMetricReader(registry=custom_registry)
-        # global REGISTRY should NOT be used
-        self._mock_registry_register.assert_not_called()
-        # check custom_registry was registered
-        self.assertIn(reader._collector, custom_registry._names_to_collectors.values())
-        reader.shutdown()
+        with self._registry_register_patch:
+            custom_registry = CollectorRegistry()
+            reader = PrometheusMetricReader(registry=custom_registry)
+            # global REGISTRY should NOT be used
+            self._mock_registry_register.assert_not_called()
+            # check custom_registry was registered
+            self.assertIn(reader._collector, custom_registry._collector_to_names)
+            reader.shutdown()
+
+
 
     def verify_text_format(
         self, metric: Metric, expect_prometheus_text: str, prefix: str = ""