Audit and test opentelemetry-instrumentation-wsgi NoOpTracerProvider (#1610)

Author: Akochavi

instrumentation/opentelemetry-instrumentation-wsgi/tests/test_wsgi_middleware.py

@@ -484,6 +484,21 @@ def test_basic_wsgi_call(self):
         response = app(self.environ, self.start_response)
         self.validate_response(response, exporter)
 
+    def test_no_op_tracer_provider(self):
+        app = otel_wsgi.OpenTelemetryMiddleware(
+            simple_wsgi, tracer_provider=trace_api.NoOpTracerProvider()
+        )
+
+        response = app(self.environ, self.start_response)
+        while True:
+            try:
+                value = next(response)
+                self.assertEqual(value, b"*")
+            except StopIteration:
+                break
+        span_list = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(span_list), 0)
+
 
 class TestWsgiMiddlewareWrappedWithAnotherFramework(WsgiTestBase):
     def test_mark_span_internal_in_presence_of_span_from_other_framework(self):