TST: assert_produces_warning works with filterwarnings

pandas/tests/util/test_assert_produces_warning.py

@@ -0,0 +1,23 @@
+import warnings
+
+import pytest
+
+import pandas.util.testing as tm
+
+
+def f(a=FutureWarning, b=RuntimeWarning):
+    warnings.warn('f1', a)
+    warnings.warn('f2', b)
+
+
+@pytest.mark.filterwarnings('ignore:f1:FutureWarning')
+@pytest.mark.filterwarnings('ignore:f2:RuntimeWarning')
+def test_assert_produces_warning_honors_filter():
+    with tm.assert_produces_warning(RuntimeWarning):
+        f()
+
+
+@pytest.mark.filterwarnings('ignore:f1:FutureWarning')
+def test_assert_produces_warning_message():
+    with tm.assert_produces_warning(FutureWarning, message='f2'):
+        f(FutureWarning, FutureWarning)

pandas/util/testing.py

@@ -2571,7 +2571,8 @@ def exception_matches(self, exc_type, exc_value, trace_back):
 
 @contextmanager
 def assert_produces_warning(expected_warning=Warning, filter_level="always",
-                            clear=None, check_stacklevel=True):
+                            clear=None, check_stacklevel=True,
+                            message=''):
     """
     Context manager for running code expected to either raise a specific
     warning, or not raise any warnings. Verifies that the code raises the
@@ -2584,7 +2585,7 @@ def assert_produces_warning(expected_warning=Warning, filter_level="always",
         The type of Exception raised. ``exception.Warning`` is the base
         class for all warnings. To check that no warning is returned,
         specify ``False`` or ``None``.
-    filter_level : str, default "always"
+    filter_level : str or None, default "always"
         Specifies whether warnings are ignored, displayed, or turned
         into errors.
         Valid values are:
@@ -2597,6 +2598,7 @@ class for all warnings. To check that no warning is returned,
         * "module" - print the warning the first time it is generated
           from each module
         * "once" - print the warning the first time it is generated
+        * None - do not apply a new filter
 
     clear : str, default None
         If not ``None`` then remove any previously raised warnings from
@@ -2608,6 +2610,9 @@ class for all warnings. To check that no warning is returned,
         If True, displays the line that called the function containing
         the warning to show were the function is called. Otherwise, the
         line that implements the function is displayed.
+    message : str, default ''
+        Use in the filter with `filter_level` and `expected_warning`
+        the control which warnings the filter applies to.
 
     Examples
     --------
@@ -2646,7 +2651,11 @@ class for all warnings. To check that no warning is returned,
                     pass
 
         saw_warning = False
-        warnings.simplefilter(filter_level)
+        if expected_warning and filter_level:
+            warnings.filterwarnings(filter_level, message, expected_warning)
+        elif filter_level:
+            # no expected warnings.
+            warnings.simplefilter(filter_level)
         yield w
         extra_warnings = []