The ids arguments of fixture_union, param_fixture[s], etc. now also support infinite generators. Improved fix for #148

Author: Sylvain MARIE

pytest_cases/common_pytest.py

@@ -223,10 +223,8 @@ def make_test_ids(global_ids, id_marks, argnames=None, argvalues=None, precomput
     """
     if global_ids is not None:
         # overridden at global pytest.mark.parametrize level - this takes precedence.
-        try:  # an explicit list of ids ?
-            p_ids = list(id for id, v in zip(global_ids, argvalues))
-        except TypeError:  # a callable to apply on the values
-            p_ids = list(global_ids(v) for v in argvalues)
+        # resolve possibly infinite generators of ids here
+        p_ids = resolve_ids(global_ids, argvalues)
     else:
         # default: values-based
         if precomputed_ids is not None:
@@ -243,6 +241,16 @@ def make_test_ids(global_ids, id_marks, argnames=None, argvalues=None, precomput
     return p_ids
 
 
+def resolve_ids(ids, argvalues):
+    """Returns the list of ids to use by a parametrized fixture, based on the `ids` parameter and the `argvalues`"""
+
+    try:  # an explicit list or generator of ids ?
+        p_ids = list(id for id, v in zip(ids, argvalues))
+    except TypeError:  # a callable to apply on the values
+        p_ids = list(ids(v) for v in argvalues)
+    return p_ids
+
+
 def make_test_ids_from_param_values(param_names,
                                     param_values,
                                     ):

pytest_cases/fixture_core1_unions.py

@@ -17,14 +17,14 @@
     from funcsigs import signature, Parameter  # noqa
 
 try:  # type hints, python 3+
-    from typing import Callable, Union, Optional, Any, List, Iterable, Sequence  # noqa
+    from typing import Callable, Union, Optional, Any, List, Iterable, Sequence, Generator  # noqa
     from types import ModuleType  # noqa
 except ImportError:
     pass
 
 from .common_mini_six import string_types
 from .common_pytest import get_fixture_name, is_marked_parameter_value, get_marked_parameter_values, pytest_fixture, \
-    extract_parameterset_info, get_param_argnames_as_list, get_fixture_scope
+    extract_parameterset_info, get_param_argnames_as_list, get_fixture_scope, resolve_ids
 from .fixture__creation import get_caller_module, check_name_available, WARN
 
 
@@ -208,7 +208,7 @@ def fixture_union(name,                # type: str
                   fixtures,            # type: Iterable[Union[str, Callable]]
                   scope="function",    # type: str
                   idstyle='explicit',  # type: Optional[str]
-                  ids=None,            # type: Union[Callable, List[str]]
+                  ids=None,            # type: Union[Callable, List[str], Generator[str, None, None]]
                   unpack_into=None,    # type: Iterable[str]
                   autouse=False,       # type: bool
                   hook=None,           # type: Callable[[Callable], Callable]
@@ -292,7 +292,7 @@ def _fixture_union(fixtures_dest,
                    unique_fix_alt_names,  # type: List[str]
                    scope="function",      # type: str
                    idstyle="explicit",    # type: str
-                   ids=None,              # type: Union[Callable, List[str]]
+                   ids=None,              # type: Union[Callable, List[str], Generator[str, None, None]]
                    autouse=False,         # type: bool
                    hook=None,             # type: Callable[[Callable], Callable]
                    caller=fixture_union,  # type: Callable
@@ -338,9 +338,15 @@ def _new_fixture(request, **all_fixtures):
                 raise TypeError("Union Fixture %s received invalid parameter type: %s. Please report this issue."
                                 "" % (name, _alternative.__class__))
 
+    if ids is None:
+        ids = UnionIdMakers.get(idstyle)
+    else:
+        # resolve possibly infinite generators of ids here
+        ids = resolve_ids(ids, fix_alternatives)
+
     # finally create the fixture per se.
     _make_fix = pytest_fixture(scope=scope, params=fix_alternatives, autouse=autouse,
-                               ids=ids or UnionIdMakers.get(idstyle), hook=hook, **kwargs)
+                               ids=ids, hook=hook, **kwargs)
     new_union_fix = _make_fix(_new_fixture)
 
     # Dynamically add fixture to caller's module as explained in https://github.com/pytest-dev/pytest/issues/2424

pytest_cases/fixture_core2.py

@@ -20,22 +20,23 @@
     from funcsigs import signature, Parameter  # noqa
 
 try:  # type hints, python 3+
-    from typing import Callable, Union, Any, List, Iterable, Sequence  # noqa
+    from typing import Callable, Union, Any, List, Iterable, Sequence, Generator  # noqa
     from types import ModuleType  # noqa
 except ImportError:
     pass
 
 from .common_pytest_lazy_values import get_lazy_args
 from .common_pytest import get_pytest_parametrize_marks, make_marked_parameter_value, get_param_argnames_as_list, \
-    analyze_parameter_set, combine_ids, is_marked_parameter_value, get_marked_parameter_values, pytest_fixture
+    analyze_parameter_set, combine_ids, is_marked_parameter_value, get_marked_parameter_values, pytest_fixture, \
+    resolve_ids
 from .fixture__creation import get_caller_module, check_name_available, WARN, CHANGE
 from .fixture_core1_unions import ignore_unused, is_used_request, NOT_USED, _make_unpack_fixture
 
 
 def param_fixture(argname,           # type: str
                   argvalues,         # type: Iterable[Any]
                   autouse=False,     # type: bool
-                  ids=None,          # type: Union[Callable, List[str]]
+                  ids=None,          # type: Union[Callable, List[str], Generator[str, None, None]]
                   scope="function",  # type: str
                   hook=None,         # type: Callable[[Callable], Callable]
                   debug=False,       # type: bool
@@ -89,7 +90,7 @@ def _create_param_fixture(fixtures_dest,
                           argname,           # type: str
                           argvalues,         # type: Sequence[Any]
                           autouse=False,     # type: bool
-                          ids=None,          # type: Union[Callable, List[str]]
+                          ids=None,          # type: Union[Callable, List[str], Generator[str, None, None]]
                           scope="function",  # type: str
                           hook=None,         # type: Callable[[Callable], Callable]
                           auto_simplify=False,
@@ -134,7 +135,7 @@ def __param_fixture(request):
 def param_fixtures(argnames,          # type: str
                    argvalues,         # type: Iterable[Any]
                    autouse=False,     # type: bool
-                   ids=None,          # type: Union[Callable, List[str]]
+                   ids=None,          # type: Union[Callable, List[str], Generator[str, None, None]]
                    scope="function",  # type: str
                    hook=None,         # type: Callable[[Callable], Callable]
                    debug=False,       # type: bool
@@ -192,7 +193,7 @@ def _create_params_fixture(fixtures_dest,
                            argnames_lst,      # type: Sequence[str]
                            argvalues,         # type: Sequence[Any]
                            autouse=False,     # type: bool
-                           ids=None,          # type: Union[Callable, List[str]]
+                           ids=None,          # type: Union[Callable, List[str], Generator[str, None, None]]
                            scope="function",  # type: str
                            hook=None,         # type: Callable[[Callable], Callable]
                            debug=False,       # type: bool
@@ -377,6 +378,11 @@ def _decorate_fixture_plus(fixture_func,
         # make the fixture union-aware
         wrapped_fixture_func = ignore_unused(fixture_func)
 
+        # resolve possibly infinite generators of ids here
+        if 'params' in kwargs and 'ids' in kwargs:
+            if kwargs['ids'] is not None:
+                kwargs['ids'] = resolve_ids(kwargs['ids'], kwargs['params'])
+
         # transform the created wrapper into a fixture
         return pytest_fixture(scope=scope, autouse=autouse, hook=hook, **kwargs)(wrapped_fixture_func)
 

pytest_cases/fixture_parametrize_plus.py

@@ -39,7 +39,7 @@ def _fixture_product(fixtures_dest,
                      fixtures_or_values,
                      fixture_positions,
                      scope="function",    # type: str
-                     ids=None,            # type: Union[Callable, List[str]]
+                     ids=None,            # type: Union[Callable, List[str], Generator[str, None, None]]
                      unpack_into=None,    # type: Iterable[str]
                      autouse=False,       # type: bool
                      hook=None,           # type: Callable[[Callable], Callable]
@@ -378,7 +378,7 @@ def __repr__(self):
 def _parametrize_plus(argnames=None,
                       argvalues=None,
                       indirect=False,      # type: bool
-                      ids=None,            # type: Union[Callable, List[str]]
+                      ids=None,            # type: Union[Callable, List[str], Generator[str, None, None]]
                       idstyle='explicit',  # type: str
                       idgen=_IDGEN,        # type: Union[str, Callable]
                       scope=None,          # type: str

pytest_cases/tests/pytest_extension/issues/test_issue_148.py

@@ -1,29 +1,39 @@
 import itertools as itt
 
-from pytest_cases import parametrize, fixture
+from pytest_cases import parametrize, fixture, param_fixtures, fixture_union
 
 
-def mygen():
+def mygen(name):
     """An infinite generator of ids"""
     for i in itt.count():
-        yield "x{%i}" % i
+        yield "%s{%i}" % (name, i)
 
 
 @fixture()
-@parametrize("y", [0, 1], ids=("x{%i}" % i for i in itt.count()))
-@parametrize("x", [1, 2], ids=mygen())
+@parametrize("y", [0, 1], ids=("y{%i}" % i for i in itt.count()))
+@parametrize("x", [1, 2], ids=mygen("x"))
 def my_fixture(x, y):
     return x, y
 
 
-def test_foo(my_fixture):
+a = param_fixtures("a", ['aa', 'ab'], ids=mygen("a"))
+
+
+my_union = fixture_union("my_union", [a], ids=mygen("myunion"))
+
+
+def test_foo(my_fixture, my_union, a):
     pass
 
 
 def test_synthesis(module_results_dct):
     assert list(module_results_dct) == [
-        'test_foo[x{0}-x{0}]',
-        'test_foo[x{0}-x{1}]',
-        'test_foo[x{1}-x{0}]',
-        'test_foo[x{1}-x{1}]'
+        'test_foo[x{0}-y{0}-myunion{0}-a{0}]',
+        'test_foo[x{0}-y{0}-myunion{0}-a{1}]',
+        'test_foo[x{0}-y{1}-myunion{0}-a{0}]',
+        'test_foo[x{0}-y{1}-myunion{0}-a{1}]',
+        'test_foo[x{1}-y{0}-myunion{0}-a{0}]',
+        'test_foo[x{1}-y{0}-myunion{0}-a{1}]',
+        'test_foo[x{1}-y{1}-myunion{0}-a{0}]',
+        'test_foo[x{1}-y{1}-myunion{0}-a{1}]'
     ]