From bb878f9ae6fc350ce492f5349b54defd503ad0e8 Mon Sep 17 00:00:00 2001
From: Vladyslav Rachek <elektrofootball@gmail.com>
Date: Sun, 8 Dec 2019 11:17:04 +0100
Subject: [PATCH] Force explicit declaration of args in parametrize

Every argname used in `parametrize` either must
be declared explicitly in the python test function, or via
`indirect` list

References https://github.com/pytest-dev/pytest/issues/5712

TODO: as of now, ValueError occurs during collection phase. Maybe we
want it to appear during other phase?
---
 AUTHORS                        |  1 +
 doc/en/example/parametrize.rst |  3 ++-
 src/_pytest/python.py          | 31 ++++++++++++++++++++++++++++
 testing/python/metafunc.py     | 37 ++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/AUTHORS b/AUTHORS
index 6e2f472fe4a..6252be8ddae 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -265,6 +265,7 @@ Vidar T. Fauske
 Virgil Dupras
 Vitaly Lashmanov
 Vlad Dragos
+Vladyslav Rachek
 Volodymyr Piskun
 Wei Lin
 Wil Cooley
diff --git a/doc/en/example/parametrize.rst b/doc/en/example/parametrize.rst
index 7230f2b00db..5c765e83b02 100644
--- a/doc/en/example/parametrize.rst
+++ b/doc/en/example/parametrize.rst
@@ -396,7 +396,8 @@ The result of this test will be successful:
 
     ========================== no tests ran in 0.12s ===========================
 
-.. regendoc:wipe
+Note, that each argument in `parametrize` list should be explicitly declared in corresponding
+python test function or via `indirect`.
 
 Parametrizing test methods through per-class configuration
 --------------------------------------------------------------
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index d787638c9f1..c69653fc9fc 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -974,6 +974,7 @@ def parametrize(self, argnames, argvalues, indirect=False, ids=None, scope=None)
             scope = _find_parametrized_scope(argnames, self._arg2fixturedefs, indirect)
 
         self._validate_if_using_arg_names(argnames, indirect)
+        self._validate_explicit_parameters(argnames, indirect)
 
         arg_values_types = self._resolve_arg_value_types(argnames, indirect)
 
@@ -1096,6 +1097,36 @@ def _validate_if_using_arg_names(self, argnames, indirect):
                         pytrace=False,
                     )
 
+    def _validate_explicit_parameters(self, argnames, indirect):
+        """
+        The argnames in *parametrize* should either be declared explicitly via
+        indirect list or explicitly in the function
+
+        :param List[str] argnames: list of argument names passed to ``parametrize()``.
+        :param indirect: same ``indirect`` parameter of ``parametrize()``.
+        :raise ValueError: if validation fails
+        """
+        func_name = self.function.__name__
+        if type(indirect) is bool and indirect is True:
+            return
+        parametrized_argnames = list()
+        funcargnames = _pytest.compat.getfuncargnames(self.function)
+        if type(indirect) is list:
+            for arg in argnames:
+                if arg not in indirect:
+                    parametrized_argnames.append(arg)
+        elif indirect is False:
+            parametrized_argnames = argnames
+        for arg in parametrized_argnames:
+            # reference: https://docs.python.org/3/library/inspect.html#inspect.getfullargspec
+            # this will contain args, vargargs, and everything python function can have
+            if arg not in funcargnames:
+                raise ValueError(
+                    f'In function "{func_name}":\n'
+                    f'Parameter "{arg}" should be declared explicitly via indirect\n'
+                    f"or in function itself"
+                )
+
 
 def _find_parametrized_scope(argnames, arg2fixturedefs, indirect):
     """Find the most appropriate scope for a parametrized call based on its arguments.
diff --git a/testing/python/metafunc.py b/testing/python/metafunc.py
index 65855f724ac..0fb1452adf3 100644
--- a/testing/python/metafunc.py
+++ b/testing/python/metafunc.py
@@ -1780,3 +1780,40 @@ def test_foo(a):
         )
         result = testdir.runpytest()
         result.assert_outcomes(passed=1)
+
+    def test_parametrize_explicit_parameters_func(self, testdir):
+        testdir.makepyfile(
+            """
+            import pytest
+
+
+            @pytest.fixture
+            def fixture(arg):
+                return arg
+
+            @pytest.mark.parametrize("arg", ["baz"])
+            def test_without_arg(fixture):
+                assert "baz" == fixture
+        """
+        )
+        result = testdir.runpytest()
+        result.assert_outcomes(error=1)
+
+    def test_parametrize_explicit_parameters_method(self, testdir):
+        testdir.makepyfile(
+            """
+            import pytest
+
+            class Test:
+                @pytest.fixture
+                def test_fixture(self, argument):
+                    return argument
+
+                @pytest.mark.parametrize("argument", ["foobar"])
+                def test_without_argument(self, test_fixture):
+                    assert "foobar" == test_fixture
+        """
+        )
+        result = testdir.runpytest()
+        result.assert_outcomes(error=1)
+        # assert result.ret == ExitCode.INTERRUPTED # ???