Verify custom resource attributes support (#32).

Co-authored-by: p-pautov <37922380+p-pautov@users.noreply.github.com>

tests/trace_service.py

@@ -14,16 +14,20 @@ class TraceService(trace_service_pb2_grpc.TraceServiceServicer):
         self.batches.append(request.resource_spans)
         return trace_service_pb2.ExportTracePartialSuccess()
 
-    def get_span(self):
+    def get_batch(self):
         for _ in range(10):
             if len(self.batches):
                 break
             time.sleep(0.001)
+        assert len(self.batches) == 1
+        assert len(self.batches[0]) == 1
+        return self.batches.pop()[0]
 
-        assert len(self.batches) == 1, "No spans received"
-        span = self.batches[0][0].scope_spans[0].spans.pop()
-        self.batches.clear()
-        return span
+    def get_span(self):
+        batch = self.get_batch()
+        assert len(batch.scope_spans) == 1
+        assert len(batch.scope_spans[0].spans) == 1
+        return batch.scope_spans[0].spans.pop()
 
 
 @pytest.fixture(scope="module")