Added test_pytest_make_parametrize_id

_pytest/python.py

@@ -1133,7 +1133,7 @@ else:
             return val.encode('unicode-escape')
 
 
-def _idval(val, argname, idx, idfn, config):
+def _idval(val, argname, idx, idfn, config=None):
     if idfn:
         try:
             s = idfn(val)
@@ -1159,7 +1159,7 @@ def _idval(val, argname, idx, idfn, config):
         return val.__name__
     return str(argname)+str(idx)
 
-def _idvalset(idx, valset, argnames, idfn, ids, config):
+def _idvalset(idx, valset, argnames, idfn, ids, config=None):
     if ids is None or ids[idx] is None:
         this_id = [_idval(val, argname, idx, idfn, config)
                    for val, argname in zip(valset, argnames)]

testing/python/metafunc.py

@@ -1156,3 +1156,21 @@ class TestMarkersWithParametrization:
         """)
         reprec = testdir.inline_run()
         reprec.assertoutcome(passed=2)
+
+    def test_pytest_make_parametrize_id(self, testdir):
+        testdir.makeconftest("""
+            def pytest_make_parametrize_id(val):
+                return str(val * 2)
+        """)
+        testdir.makepyfile("""
+                import pytest
+
+                @pytest.mark.parametrize("x", range(2))
+                def test_func(x):
+                    pass
+                """)
+        result = testdir.runpytest("-v")
+        result.stdout.fnmatch_lines([
+            "*test_func*0*PASS*",
+            "*test_func*2*PASS*",
+        ])