Fix empty params

Author: Anton3

src/_pytest/python.py

@@ -475,14 +475,13 @@ def _genfunctions(self, name: str, funcobj) -> Iterator[Function]:
             fixtureinfo.prune_dependency_tree()
 
             for callspec in metafunc._calls:
-                params_id = callspec.id
-                subname = f"{name}[{params_id}]" if params_id else name
+                subname = f"{name}[{callspec.id}]" if callspec._idlist else name
                 yield Function.from_parent(
                     self,
                     name=subname,
                     callspec=callspec,
                     fixtureinfo=fixtureinfo,
-                    keywords={params_id: True},
+                    keywords={callspec.id: True},
                     originalname=name,
                 )
 
@@ -1086,7 +1085,7 @@ def setmulti(
             params=params,
             indices=indices,
             _arg2scope=arg2scope,
-            _idlist=[*self._idlist, id] if id else self._idlist,
+            _idlist=[*self._idlist, id] if id is not None else self._idlist,
             marks=[*self.marks, *normalize_mark_list(marks)],
         )
 

testing/python/metafunc.py

@@ -2149,7 +2149,7 @@ class TestHiddenParam:
     """Test that pytest.HIDDEN_PARAM works"""
 
     def test_parametrize_ids(self, pytester: Pytester) -> None:
-        pytester.makepyfile(
+        items = pytester.getitems(
             """
             import pytest
 
@@ -2166,18 +2166,15 @@ def test_func(foo, bar):
                 pass
         """
         )
-        result = pytester.runpytest("-vv", "-s")
-        result.stdout.fnmatch_lines(
-            [
-                "test_parametrize_ids.py::test_func[paramset1] PASSED",
-                "test_parametrize_ids.py::test_func PASSED",
-                "test_parametrize_ids.py::test_func[paramset3] PASSED",
-                "*= 3 passed in *",
-            ]
-        )
+        names = [item.name for item in items]
+        assert names == [
+            "test_func[paramset1]",
+            "test_func",
+            "test_func[paramset3]",
+        ]
 
     def test_param_id(self, pytester: Pytester) -> None:
-        pytester.makepyfile(
+        items = pytester.getitems(
             """
             import pytest
 
@@ -2193,15 +2190,12 @@ def test_func(foo, bar):
                 pass
         """
         )
-        result = pytester.runpytest("-vv", "-s")
-        result.stdout.fnmatch_lines(
-            [
-                "test_param_id.py::test_func[paramset1] PASSED",
-                "test_param_id.py::test_func PASSED",
-                "test_param_id.py::test_func[c-z] PASSED",
-                "*= 3 passed in *",
-            ]
-        )
+        names = [item.name for item in items]
+        assert names == [
+            "test_func[paramset1]",
+            "test_func",
+            "test_func[c-z]",
+        ]
 
     def test_multiple_hidden_param_is_forbidden(self, pytester: Pytester) -> None:
         pytester.makepyfile(
@@ -2235,7 +2229,7 @@ def test_func(foo, bar):
         )
 
     def test_multiple_parametrize(self, pytester: Pytester) -> None:
-        pytester.makepyfile(
+        items = pytester.getitems(
             """
             import pytest
 
@@ -2252,13 +2246,10 @@ def test_func(foo, bar):
                 pass
         """
         )
-        result = pytester.runpytest("-vv", "-s")
-        result.stdout.fnmatch_lines(
-            [
-                "test_multiple_parametrize.py::test_func[a-x] PASSED",
-                "test_multiple_parametrize.py::test_func[a-y] PASSED",
-                "test_multiple_parametrize.py::test_func[x] PASSED",
-                "test_multiple_parametrize.py::test_func[y] PASSED",
-                "*= 4 passed in *",
-            ]
-        )
+        names = [item.name for item in items]
+        assert names == [
+            "test_func[a-x]",
+            "test_func[a-y]",
+            "test_func[x]",
+            "test_func[y]",
+        ]