TST: Fail if parameterize set is empty (#48924)

Author: mroeschke

pandas/tests/computation/test_eval.py

@@ -77,11 +77,6 @@ def parser(request):
     return request.param
 
 
-@pytest.fixture(params=list(_unary_math_ops) if NUMEXPR_INSTALLED else [])
-def unary_fns_for_ne(request):
-    return request.param
-
-
 def _eval_single_bin(lhs, cmp1, rhs, engine):
     c = _binary_ops_dict[cmp1]
     if ENGINES[engine].has_neg_frac:
@@ -1579,12 +1574,14 @@ def eval(self, *args, **kwargs):
         kwargs["level"] = kwargs.pop("level", 0) + 1
         return pd.eval(*args, **kwargs)
 
-    def test_unary_functions(self, unary_fns_for_ne):
+    @pytest.mark.skipif(
+        not NUMEXPR_INSTALLED, reason="Unary ops only implemented for numexpr"
+    )
+    @pytest.mark.parametrize("fn", _unary_math_ops)
+    def test_unary_functions(self, fn):
         df = DataFrame({"a": np.random.randn(10)})
         a = df.a
 
-        fn = unary_fns_for_ne
-
         expr = f"{fn}(a)"
         got = self.eval(expr)
         with np.errstate(all="ignore"):

pyproject.toml

@@ -67,6 +67,7 @@ disable = [
 # sync minversion with pyproject.toml & install.rst
 minversion =  "6.0"
 addopts = "--strict-data-files --strict-markers --strict-config --capture=no --durations=30 --junitxml=test-data.xml"
+empty_parameter_set_mark = "fail_at_collect"
 xfail_strict = true
 testpaths = "pandas"
 doctest_optionflags = [