Fix @parametrize when using an integer and strings as parameters in a test accepting a parameter and a fixture as arguments.

testing/test_parametrize_with_fixture.py

@@ -0,0 +1,24 @@
+
+
+def test_parametrize(testdir):
+    testdir.makepyfile("""
+        import pytest
+
+        @pytest.fixture
+        def myfixture():
+            return 'example'
+
+
+        @pytest.mark.parametrize(
+            'limit',
+            (
+                0,
+                '0',
+                'foo',
+            )
+        )
+        def test_limit(limit, myfixture):
+            return
+    """)
+    reprec = testdir.runpytest()
+    assert 'KeyError' in reprec.stdout