Add test_load_runtime_context_fallback

Author: WqyJh

opentelemetry-api/src/opentelemetry/context/__init__.py

@@ -60,7 +60,7 @@ def _load_runtime_context() -> typing.Optional[_RuntimeContext]:
             iter(  # type: ignore
                 entry_points(  # type: ignore
                     group="opentelemetry_context",
-                    name=OTEL_PYTHON_CONTEXT,
+                    name=default_context,
                 )
             )
         ).load()()

opentelemetry-api/tests/context/test_context.py

@@ -88,3 +88,8 @@ def test_load_runtime_context_default(self):
     def test_load_runtime_context(self):
         ctx = context._load_runtime_context()  # pylint: disable=W0212
         self.assertIsInstance(ctx, ContextVarsRuntimeContext)
+
+    @patch.dict("os.environ", {OTEL_PYTHON_CONTEXT: "foo"})
+    def test_load_runtime_context_fallback(self):
+        ctx = context._load_runtime_context()  # pylint: disable=W0212
+        self.assertIsInstance(ctx, ContextVarsRuntimeContext)