Add test to design warns signature in TDD mimicking raises signature

Author: Joan Massich

testing/test_recwarn.py

@@ -284,3 +284,27 @@ def test(run):
         ''')
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(['*2 passed in*'])
+
+    def test_message_using(self):
+        source = "warnings.warn('my runtime warning', RuntimeWarning)"
+        pytest.warns(RuntimeWarning, source, message='my runtime warning')
+
+    def test_message_using_contextmanager(self):
+        with pytest.warns(RuntimeWarning, message='my runtime warning'):
+            warnings.warn("my runtime warning", RuntimeWarning)
+
+        with pytest.raises(AssertionError, match='is different from'):
+            with pytest.warns(RuntimeWarning, message="my runtime warning"):
+                warnings.warn("different message", RuntimeWarning)
+
+    def test_match_regex(self):
+        source = "warnings.warn('value must be 42', UserWarning)"
+        pytest.warns(UserWarning, source, match=r'must be \d+$')
+
+    def test_match_regex_using_contextmanager(self):
+        with pytest.warns(UserWarning, match=r'must be \d+$'):
+            warnings.warn("value must be 42", UserWarning)
+
+        with pytest.raises(AssertionError, match='pattern not found'):
+            with pytest.warns(UserWarning, match=r'must be \d+$'):
+                warnings.warn("this is not here", UserWarning)