Issue 460: getfuncargvalue fixture w. params err

Author: tomviner

AUTHORS

@@ -89,6 +89,7 @@ Ryan Wooden
 Samuele Pedroni
 Simon Gomizelj
 Stefano Taschini
+Stefan Farmbauer
 Thomas Grainger
 Tom Viner
 Trevor Bekolay

CHANGELOG.rst

@@ -6,7 +6,7 @@
 * Text documents without any doctests no longer appear as "skipped".
   Thanks `@graingert`_ for reporting and providing a full PR (`#1580`_).
 
-* Fix internal error issue when ``method`` argument is missing for 
+* Fix internal error issue when ``method`` argument is missing for
   ``teardown_method()``. Fixes (`#1605`_).
 
 * Fix exception visualization in case the current working directory (CWD) gets
@@ -17,14 +17,20 @@
   is specified on the command line together with the ``--pyargs``
   option.  Thanks to `@taschini`_ for the PR (`#1597`_).
 
-*
+* Raise helpful failure message, when requesting parametrized fixture at runtime,
+  e.g. with ``request.getfuncargvalue``. BACKWARD INCOMPAT: Previously these params
+  were simply never defined, now a failure is raised. Fixes (`#460`_). Thanks to
+  `@nikratio`_ for bug report, `@RedBeardCode`_ and `@tomviner`_ for PR.
 
 .. _#1580: https://github.com/pytest-dev/pytest/pull/1580
 .. _#1605: https://github.com/pytest-dev/pytest/issues/1605
 .. _#1597: https://github.com/pytest-dev/pytest/pull/1597
+.. _#460: https://github.com/pytest-dev/pytest/pull/460
 
 .. _@graingert: https://github.com/graingert
 .. _@taschini: https://github.com/taschini
+.. _@nikratio: https://github.com/nikratio
+.. _@RedBeardCode: https://github.com/RedBeardCode
 
 
 2.9.2

_pytest/python.py

@@ -1651,6 +1651,25 @@ def _getfuncargvalue(self, fixturedef):
         except (AttributeError, ValueError):
             param = NOTSET
             param_index = 0
+            if fixturedef.params is not None:
+                frame = inspect.stack()[3]
+                frameinfo = inspect.getframeinfo(frame[0])
+                source_path = frameinfo.filename
+                source_lineno = frameinfo.lineno
+                source_path = py.path.local(source_path)
+                if source_path.relto(funcitem.config.rootdir):
+                    source_path = source_path.relto(funcitem.config.rootdir)
+                msg = (
+                    "The requested fixture has no parameter defined for the "
+                    "current test.\n\nRequested fixture '{0}' defined in:\n{1}"
+                    "\n\nRequested here:\n{2}:{3}".format(
+                        fixturedef.argname,
+                        getlocation(fixturedef.func, funcitem.config.rootdir),
+                        source_path,
+                        source_lineno,
+                    )
+                )
+                pytest.fail(msg)
         else:
             # indices might not be set if old-style metafunc.addcall() was used
             param_index = funcitem.callspec.indices.get(argname, 0)

testing/python/fixture.py

@@ -2723,3 +2723,108 @@ def test_1(arg1):
             *def arg1*
         """)
 
+class TestParameterizedSubRequest:
+    def test_call_from_fixture(self, testdir):
+        testfile = testdir.makepyfile("""
+            import pytest
+
+            @pytest.fixture(params=[0, 1, 2])
+            def fix_with_param(request):
+                return request.param
+
+            @pytest.fixture
+            def get_named_fixture(request):
+                return request.getfuncargvalue('fix_with_param')
+
+            def test_foo(request, get_named_fixture):
+                pass
+            """)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("""
+            E*Failed: The requested fixture has no parameter defined for the current test.
+            E*
+            E*Requested fixture 'fix_with_param' defined in:
+            E*{0}:4
+            E*Requested here:
+            E*{1}:9
+            *1 error*
+            """.format(testfile.basename, testfile.basename))
+
+    def test_call_from_test(self, testdir):
+        testfile = testdir.makepyfile("""
+            import pytest
+
+            @pytest.fixture(params=[0, 1, 2])
+            def fix_with_param(request):
+                return request.param
+
+            def test_foo(request):
+                request.getfuncargvalue('fix_with_param')
+            """)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("""
+            E*Failed: The requested fixture has no parameter defined for the current test.
+            E*
+            E*Requested fixture 'fix_with_param' defined in:
+            E*{0}:4
+            E*Requested here:
+            E*{1}:8
+            *1 failed*
+            """.format(testfile.basename, testfile.basename))
+
+    def test_external_fixture(self, testdir):
+        conffile = testdir.makeconftest("""
+            import pytest
+
+            @pytest.fixture(params=[0, 1, 2])
+            def fix_with_param(request):
+                return request.param
+            """)
+
+        testfile = testdir.makepyfile("""
+            def test_foo(request):
+                request.getfuncargvalue('fix_with_param')
+            """)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("""
+            E*Failed: The requested fixture has no parameter defined for the current test.
+            E*
+            E*Requested fixture 'fix_with_param' defined in:
+            E*{0}:4
+            E*Requested here:
+            E*{1}:2
+            *1 failed*
+            """.format(conffile.basename, testfile.basename))
+
+    def test_non_relative_path(self, testdir):
+        tests_dir = testdir.mkdir('tests')
+        fixdir = testdir.mkdir('fixtures')
+        fixfile = fixdir.join("fix.py")
+        fixfile.write(_pytest._code.Source("""
+            import pytest
+
+            @pytest.fixture(params=[0, 1, 2])
+            def fix_with_param(request):
+                return request.param
+            """))
+
+        testfile = tests_dir.join("test_foos.py")
+        testfile.write(_pytest._code.Source("""
+            from fix import fix_with_param
+
+            def test_foo(request):
+                request.getfuncargvalue('fix_with_param')
+            """))
+
+        tests_dir.chdir()
+        testdir.syspathinsert(fixdir)
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines("""
+            E*Failed: The requested fixture has no parameter defined for the current test.
+            E*
+            E*Requested fixture 'fix_with_param' defined in:
+            E*{0}:5
+            E*Requested here:
+            E*{1}:5
+            *1 failed*
+            """.format(fixfile.strpath, testfile.basename))