Fixed parametrization order when @pytest_fixture_plus is used with …

…several `@pytest.mark.parametrize`. Fixed #22

pytest_cases/main.py

@@ -3,6 +3,7 @@
 
 import sys
 from abc import abstractmethod, ABCMeta
+from collections import OrderedDict
 from distutils.version import LooseVersion
 from inspect import getmembers, isgeneratorfunction, getmodule
 
@@ -303,8 +304,9 @@ def decorate_pytest_fixture_plus(fixture_func,
 
     # for each dependency create an associated "param" fixture
     # Note: we could instead have created a huge parameter containing all parameters...
-    # Pros = no additional fixture. Cons: less readable and ids would be difficult to create
-    params_map = dict()
+    # Pros = no additional fixture.
+    # Cons: less readable and ids would be difficult to create
+    params_map = OrderedDict()
     for m in parametrizer_marks:
         # check what the mark specifies in terms of parameters
         if len(m.param_names) < 1:

pytest_cases/tests/simple/test_stereo_fixtures.py

@@ -40,15 +40,18 @@ def assert_state_and_move(self, path, cfg_factory):
 @pytest.mark.parametrize("cfg_factory", CFG_TYPES)   # not actual params
 def stereo_cfg(path, cfg_factory, request):
     """
-    A fixture with two parameters
+    A fixture with two parameters.
+
+    As opposed to `stereo_cfg_2`, we use here two @parametrize decorators.
+    We check that the execution order is correct.
     """
     assert isinstance(path, str)
     assert isinstance(cfg_factory, type)
     a.assert_state_and_move(path=path, cfg_factory=cfg_factory)
     return "hello"
 
 
-def test_stereo(stereo_cfg):
+def test_stereo_two_parametrizers(stereo_cfg):
     """
     A test relying on a double-parametrized fixture.
     See https://github.com/pytest-dev/pytest/issues/3960
@@ -82,7 +85,11 @@ def _id(x):
 @pytest.mark.parametrize("cfg_factory,path", product(CFG_TYPES, STEREO_PATHS), ids=_id)
 def stereo_cfg_2(path, request, cfg_factory):
     """
-    A fixture with two parameters
+    A fixture with two parameters.
+
+    As opposed to `stereo_cfg_1`, the order of the parameter is precomputed beforehand in
+    `product(CFG_TYPES, STEREO_PATHS)` and a single call to parametrize is made.
+    We check that the execution order is the same.
     """
     assert isinstance(path, str)
     assert isinstance(cfg_factory, type)
@@ -92,7 +99,7 @@ def stereo_cfg_2(path, request, cfg_factory):
     yield "hello"
 
 
-def test_stereo_2(stereo_cfg_2):
+def test_stereo_one_global_parametrizer(stereo_cfg_2):
     pass