From 34afded06dbcc4a2615043c3deaea64511d4287d Mon Sep 17 00:00:00 2001
From: Jeffrey Rackauckas <jeffreyrack@gmail.com>
Date: Tue, 27 Mar 2018 19:57:15 -0700
Subject: [PATCH] Update pytest.raises to raise a TypeError when an invalid
 keyword argument is passed.

---
 _pytest/python_api.py     | 4 ++++
 changelog/3348.bugfix.rst | 1 +
 testing/python/raises.py  | 5 +++++
 3 files changed, 10 insertions(+)
 create mode 100644 changelog/3348.bugfix.rst

diff --git a/_pytest/python_api.py b/_pytest/python_api.py
index 69ae6ed0e..5e4776ce3 100644
--- a/_pytest/python_api.py
+++ b/_pytest/python_api.py
@@ -597,6 +597,10 @@ def raises(expected_exception, *args, **kwargs):
             message = kwargs.pop("message")
         if "match" in kwargs:
             match_expr = kwargs.pop("match")
+        if len(kwargs.keys()) > 0:
+            msg = 'Unexpected keyword arguments passed to pytest.raises: '
+            msg += ', '.join(kwargs.keys())
+            raise TypeError(msg)
         return RaisesContext(expected_exception, message, match_expr)
     elif isinstance(args[0], str):
         code, = args
diff --git a/changelog/3348.bugfix.rst b/changelog/3348.bugfix.rst
new file mode 100644
index 000000000..7b56ebf98
--- /dev/null
+++ b/changelog/3348.bugfix.rst
@@ -0,0 +1 @@
+Updated `pytest.raises` to raise a TypeError when an invalid keyword argument is passed.
\ No newline at end of file
diff --git a/testing/python/raises.py b/testing/python/raises.py
index 183259f6b..156319816 100644
--- a/testing/python/raises.py
+++ b/testing/python/raises.py
@@ -61,6 +61,11 @@ class TestRaises(object):
         with pytest.raises(TypeError):
             pytest.raises('wrong', lambda: None)
 
+    def test_invalid_arguments_to_raises(self):
+        with pytest.raises(TypeError, match='unknown'):
+            with pytest.raises(TypeError, unknown='bogus'):
+                raise ValueError()
+
     def test_tuple(self):
         with pytest.raises((KeyError, ValueError)):
             raise KeyError('oops')