Fix b3 format tests (open-telemetry#1396)

mariojonke · web-flow · commit 4afa77568344 · 2020-11-24T07:13:49.000-08:00
diff --git a/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py b/opentelemetry-sdk/tests/trace/propagation/test_b3_format.py
@@ -66,6 +66,14 @@ def setUpClass(cls):
             ids_generator.generate_span_id()
         )
 
+    def setUp(self) -> None:
+        tracer_provider = trace.TracerProvider()
+        patcher = unittest.mock.patch.object(
+            trace_api, "get_tracer_provider", return_value=tracer_provider
+        )
+        patcher.start()
+        self.addCleanup(patcher.stop)
+
     def test_extract_multi_header(self):
         """Test the extraction of B3 headers."""
         child, parent, new_carrier = get_child_parent_new_carrier(
