Dependency to decorator has been dropped and replaced with makefun. Fixed #25

Author: Sylvain MARIE

ci_tools/requirements-conda.txt

@@ -5,7 +5,6 @@ pandoc
 pypandoc
 
 # --- to install
-decorator
 
 # --- to run the tests
 # (pip) pytest$PYTEST_VERSION

ci_tools/requirements-pip.txt

@@ -2,6 +2,7 @@
 pytest-runner
 
 # -- to install
+makefun
 
 # --- to generate the reports (see scripts in ci_tools, called by .travis)
 pytest-html$PYTEST_HTML_VERSION

pytest_cases/decorator_hack.py

@@ -7,8 +7,14 @@
 from distutils.version import LooseVersion
 from inspect import getmembers, isgeneratorfunction, getmodule
 
+from makefun import with_signature, add_signature_parameters, remove_signature_parameters
+
+try:  # python 3.3+
+    from inspect import signature, Parameter
+except ImportError:
+    from funcsigs import signature, Parameter
+
 from pytest_cases.common import yield_fixture, get_pytest_parametrize_marks
-from pytest_cases.decorator_hack import my_decorate
 
 try:  # type hints, python 3+
     from typing import Callable, Union, Optional, Any, Tuple, List, Dict, Iterable
@@ -379,50 +385,52 @@ def _param_fixture(request):
     old_parameter_names = tuple(v for l in params_map.values() for v in l)
 
     # common routine used below. Fills kwargs with the appropriate names and values from fixture_params
-    def _get_arguments(fixture_params, args_and_kwargs):
-        # unpack the underlying function's args/kwargs
-        args = args_and_kwargs.pop('args')
-        kwargs = args_and_kwargs.pop('kwargs')
-        if len(args_and_kwargs) > 0:
-            raise ValueError("Internal error - please file an issue in the github project page")
-
-        # fill the kwargs with additional arguments by using mapping
+    def _get_arguments(*args, **kwargs):
+        # kwargs contains the generated fixture names so we have to remove them.
+        # For each generated fixture, there are one or several parameters to inject in kwargs
         i = 0
         for new_p_name in new_parameter_names:
+            fixture_param_value = kwargs.pop(new_p_name)
             if len(params_map[new_p_name]) == 1:
-                kwargs[params_map[new_p_name][0]] = fixture_params[i]
+                # a single parameter for that generated ficture (@pytest.mark.parametrize with a single name)
+                kwargs[params_map[new_p_name][0]] = fixture_param_value
                 i += 1
             else:
-                # unpack several
-                for old_p_name, old_p_value in zip(params_map[new_p_name], fixture_params[i]):
+                # several parameters for that generated fixture (@pytest.mark.parametrize with several names)
+                # unpack all of them and inject them in the kwargs
+                for old_p_name, old_p_value in zip(params_map[new_p_name], fixture_param_value):
                     kwargs[old_p_name] = old_p_value
                     i += 1
 
         return args, kwargs
 
+    # create the new signature that we want to expose to pytest
+    old_sig = signature(fixture_func)
+    new_sig = remove_signature_parameters(old_sig, *old_parameter_names)
+    # add them in reversed order so as to match the same test order than in pytest.
+    new_sig = add_signature_parameters(new_sig, first=(Parameter(n, kind=Parameter.POSITIONAL_OR_KEYWORD)
+                                                       for n in reversed(new_parameter_names)))
+
+    # Finally create the fixture function, a wrapper of user-provided fixture with the new signature
     if not isgeneratorfunction(fixture_func):
         # normal function with return statement
-        def wrapper(f, *fixture_params, **args_and_kwargs):
-            args, kwargs = _get_arguments(fixture_params, args_and_kwargs)
+        @with_signature(new_sig)
+        def wrapped_fixture_func(*args, **kwargs):
+            args, kwargs = _get_arguments(*args, **kwargs)
             return fixture_func(*args, **kwargs)
 
-        wrapped_fixture_func = my_decorate(fixture_func, wrapper,
-                                           additional_args=new_parameter_names, removed_args=old_parameter_names)
-
         # transform the created wrapper into a fixture
         fixture_decorator = pytest.fixture(scope=scope, params=params, autouse=autouse, ids=ids, **kwargs)
         return fixture_decorator(wrapped_fixture_func)
 
     else:
         # generator function (with a yield statement)
-        def wrapper(f, *fixture_params, **args_and_kwargs):
-            args, kwargs = _get_arguments(fixture_params, args_and_kwargs)
+        @with_signature(new_sig)
+        def wrapped_fixture_func(*args, **kwargs):
+            args, kwargs = _get_arguments(*args, **kwargs)
             for res in fixture_func(*args, **kwargs):
                 yield res
 
-        wrapped_fixture_func = my_decorate(fixture_func, wrapper,
-                                           additional_args=new_parameter_names, removed_args=old_parameter_names)
-
         # transform the created wrapper into a fixture
         fixture_decorator = yield_fixture(scope=scope, params=params, autouse=autouse, ids=ids, **kwargs)
         return fixture_decorator(wrapped_fixture_func)

pytest_cases/main.py

@@ -11,7 +11,7 @@
 here = path.abspath(path.dirname(__file__))
 
 # *************** Dependencies *********
-INSTALL_REQUIRES = ['decorator', 'functools32;python_version<"3.2"', 'funcsigs;python_version<"3.3"']
+INSTALL_REQUIRES = ['makefun', 'functools32;python_version<"3.2"', 'funcsigs;python_version<"3.3"']
 DEPENDENCY_LINKS = []
 SETUP_REQUIRES = ['pytest-runner', 'setuptools_scm', 'pypandoc', 'pandoc']
 TESTS_REQUIRE = ['pytest', 'pytest-logging', 'pytest-cov', 'pytest-steps']