Fix test and add changelog entry for #3536

Author: jakewins

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Log stacktrace on `UNKNOWN` status OTLP export error 
+  ([#3536](https://github.com/open-telemetry/opentelemetry-python/pull/3536))
 - Fix OTLPExporterMixin shutdown timeout period
   ([#3524](https://github.com/open-telemetry/opentelemetry-python/pull/3524))
 

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/test_otlp_metrics_exporter.py

@@ -453,8 +453,8 @@ def test_unavailable_delay(self, mock_sleep, mock_expo):
         "opentelemetry.exporter.otlp.proto.grpc.exporter._create_exp_backoff_generator"
     )
     @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.sleep")
-    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.logger")
-    def test_unknown_logs(self, mock_sleep, mock_expo, mock_logger):
+    @patch("opentelemetry.exporter.otlp.proto.grpc.exporter.logger.error")
+    def test_unknown_logs(self, mock_logger_error, mock_sleep, mock_expo):
 
         mock_expo.configure_mock(**{"return_value": [1]})
 
@@ -465,11 +465,11 @@ def test_unknown_logs(self, mock_sleep, mock_expo, mock_logger):
             self.exporter.export(self.metrics["sum_int"]),
             MetricExportResult.FAILURE,
         )
-        mock_sleep.assert_called_with(1)
-        mock_logger.error.assert_called_with(
+        mock_sleep.assert_not_called()
+        mock_logger_error.assert_called_with(
             "Failed to export %s to %s, error code: %s",
             "metrics",
-            "TODO",
+            "localhost:4317",
             StatusCode.UNKNOWN,
             exc_info=True,
         )