Disabled test_metrics for 3.7 due to OTEL semconv imports

Author: lszinv

testing/constraints-3.7.txt

@@ -17,3 +17,4 @@ protobuf==3.20.2
 deprecated==1.2.14
 grpc-interceptor==0.15.4
 google-cloud-monitoring==2.16.0
+mmh3==4.1.0

tests/unit/test_metrics.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import pytest
 from unittest.mock import MagicMock
 from google.api_core.exceptions import ServiceUnavailable
 from google.cloud.spanner_v1.client import Client
@@ -21,6 +22,9 @@
     SpannerMetricsTracerFactory,
 )
 
+pytest.importorskip("opentelemetry")
+# Skip if semconv attributes are not present, as tracing wont' be enabled either
+pytest.importorskip("opentelemetry.semconv.attributes.otel_attributes")
 
 def test_metrics_emission_with_failure_attempt(monkeypatch):
     monkeypatch.setenv("SPANNER_ENABLE_BUILTIN_METRICS", "true")