test: migrated unit test cases from the open-telemetry#1582 to this p…

…roject

instrumentation/opentelemetry-instrumentation-threading/tests/test_threading.py

@@ -79,3 +79,107 @@ def fake_func(self):
         self.global_context = span_context
         self.global_trace_id = span_context.trace_id
         self.global_span_id = span_context.span_id
+
+    def print_square(self, num):
+        with self._tracer.start_as_current_span("square"):
+            return num * num
+
+    def print_cube(self, num):
+        with self._tracer.start_as_current_span("cube"):
+            return num * num * num
+
+    def print_square_with_thread(self, num):
+        with self._tracer.start_as_current_span("square"):
+            cube_thread = threading.Thread(target=self.print_cube, args=(10,))
+
+            cube_thread.start()
+            cube_thread.join()
+            return num * num
+
+    def calculate(self, num):
+        with self._tracer.start_as_current_span("calculate"):
+            square_thread = threading.Thread(
+                target=self.print_square, args=(num,)
+            )
+            cube_thread = threading.Thread(target=self.print_cube, args=(num,))
+            square_thread.start()
+            square_thread.join()
+
+            cube_thread.start()
+            cube_thread.join()
+
+    def test_without_thread_nesting(self):
+        square_thread = threading.Thread(target=self.print_square, args=(10,))
+
+        with self._tracer.start_as_current_span("root"):
+            square_thread.start()
+            square_thread.join()
+
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 2)
+
+        # pylint: disable=unbalanced-tuple-unpacking
+        target, root = spans[:2]
+
+        self.assertIs(target.parent, root.get_span_context())
+        self.assertIsNone(root.parent)
+
+    def test_with_thread_nesting(self):
+        #
+        #  Following scenario is tested.
+        #  threadA -> methodA -> threadB -> methodB
+        #
+
+        square_thread = threading.Thread(
+            target=self.print_square_with_thread, args=(10,)
+        )
+
+        with self._tracer.start_as_current_span("root"):
+            square_thread.start()
+            square_thread.join()
+
+        spans = self.memory_exporter.get_finished_spans()
+
+        self.assertEqual(len(spans), 3)
+        # pylint: disable=unbalanced-tuple-unpacking
+        cube, square, root = spans[:3]
+
+        self.assertIs(cube.parent, square.get_span_context())
+        self.assertIs(square.parent, root.get_span_context())
+        self.assertIsNone(root.parent)
+
+    def test_with_thread_multi_nesting(self):
+        #
+        # Following scenario is tested.
+        #                         / threadB -> methodB
+        #    threadA -> methodA ->
+        #                        \ threadC -> methodC
+        #
+        calculate_thread = threading.Thread(target=self.calculate, args=(10,))
+
+        with self._tracer.start_as_current_span("root"):
+            calculate_thread.start()
+            calculate_thread.join()
+
+        spans = self.memory_exporter.get_finished_spans()
+
+        self.assertEqual(len(spans), 4)
+
+        # pylint: disable=unbalanced-tuple-unpacking
+        cube, square, calculate, root = spans[:4]
+
+        self.assertIs(cube.parent, calculate.get_span_context())
+        self.assertIs(square.parent, calculate.get_span_context())
+        self.assertIs(calculate.parent, root.get_span_context())
+        self.assertIsNone(root.parent)
+
+    def test_uninstrumented(self):
+        ThreadingInstrumentor().uninstrument()
+
+        square_thread = threading.Thread(target=self.print_square, args=(10,))
+        square_thread.start()
+        square_thread.join()
+        spans = self.memory_exporter.get_finished_spans()
+        self.assertEqual(len(spans), 1)
+
+        ThreadingInstrumentor().instrument()