Handle match with pytest.raises()

changelog/6752.bugfix.rst

@@ -0,0 +1,3 @@
+When :py:func:`pytest.raises` is used as a function (as opposed to a context manager),
+a `match` keyword argument is now passed through to the tested function. Previously
+it was swallowed and ignored (regression in pytest 5.1.0).

src/_pytest/python_api.py

@@ -557,18 +557,16 @@ def raises(  # noqa: F811
     expected_exception: Union["Type[_E]", Tuple["Type[_E]", ...]],
     func: Callable,
     *args: Any,
-    match: Optional[str] = ...,
     **kwargs: Any
-) -> Optional[_pytest._code.ExceptionInfo[_E]]:
+) -> _pytest._code.ExceptionInfo[_E]:
     ...  # pragma: no cover
 
 
 def raises(  # noqa: F811
     expected_exception: Union["Type[_E]", Tuple["Type[_E]", ...]],
     *args: Any,
-    match: Optional[Union[str, "Pattern"]] = None,
     **kwargs: Any
-) -> Union["RaisesContext[_E]", Optional[_pytest._code.ExceptionInfo[_E]]]:
+) -> Union["RaisesContext[_E]", _pytest._code.ExceptionInfo[_E]]:
     r"""
     Assert that a code block/function call raises ``expected_exception``
     or raise a failure exception otherwise.
@@ -579,8 +577,12 @@ def raises(  # noqa: F811
         string that may contain `special characters`__, the pattern can
         first be escaped with ``re.escape``.
 
-        __ https://docs.python.org/3/library/re.html#regular-expression-syntax
+        (This is only used when ``pytest.raises`` is used as a context manager,
+        and passed through to the function otherwise.
+        When using ``pytest.raises`` as a function, you can use:
+        ``pytest.raises(Exc, func, match="passed on").match("my pattern")``.)
 
+        __ https://docs.python.org/3/library/re.html#regular-expression-syntax
 
     .. currentmodule:: _pytest._code
 
@@ -693,6 +695,7 @@ def raises(  # noqa: F811
     message = "DID NOT RAISE {}".format(expected_exception)
 
     if not args:
+        match = kwargs.pop("match", None)
         if kwargs:
             msg = "Unexpected keyword arguments passed to pytest.raises: "
             msg += ", ".join(sorted(kwargs))

testing/python/raises.py

@@ -1,3 +1,4 @@
+import re
 import sys
 
 import pytest
@@ -154,7 +155,7 @@ def test_no_raise_message(self):
         else:
             assert False, "Expected pytest.raises.Exception"
 
-    @pytest.mark.parametrize("method", ["function", "with"])
+    @pytest.mark.parametrize("method", ["function", "function_match", "with"])
     def test_raises_cyclic_reference(self, method):
         """
         Ensure pytest.raises does not leave a reference cycle (#1965).
@@ -175,6 +176,8 @@ def __call__(self):
 
         if method == "function":
             pytest.raises(ValueError, t)
+        elif method == "function_match":
+            pytest.raises(ValueError, t).match("^$")
         else:
             with pytest.raises(ValueError):
                 t()
@@ -184,7 +187,7 @@ def __call__(self):
 
         assert refcount == len(gc.get_referrers(t))
 
-    def test_raises_match(self):
+    def test_raises_match(self) -> None:
         msg = r"with base \d+"
         with pytest.raises(ValueError, match=msg):
             int("asdf")
@@ -194,13 +197,27 @@ def test_raises_match(self):
             int("asdf")
 
         msg = "with base 16"
-        expr = r"Pattern '{}' does not match \"invalid literal for int\(\) with base 10: 'asdf'\"".format(
+        expr = "Pattern {!r} does not match \"invalid literal for int() with base 10: 'asdf'\"".format(
             msg
         )
-        with pytest.raises(AssertionError, match=expr):
+        with pytest.raises(AssertionError, match=re.escape(expr)):
             with pytest.raises(ValueError, match=msg):
                 int("asdf", base=10)
 
+        # "match" without context manager.
+        pytest.raises(ValueError, int, "asdf").match("invalid literal")
+        with pytest.raises(AssertionError) as excinfo:
+            pytest.raises(ValueError, int, "asdf").match(msg)
+        assert str(excinfo.value) == expr
+
+        pytest.raises(TypeError, int, match="invalid")
+
+        def tfunc(match):
+            raise ValueError("match={}".format(match))
+
+        pytest.raises(ValueError, tfunc, match="asdf").match("match=asdf")
+        pytest.raises(ValueError, tfunc, match="").match("match=")
+
     def test_match_failure_string_quoting(self):
         with pytest.raises(AssertionError) as excinfo:
             with pytest.raises(AssertionError, match="'foo"):