Fixed bug when a test module containing @parametrize_with_cases was executed outside of pytest, typically through its __main__. Fixes #198

Author: Sylvain MARIE

pytest_cases/common_pytest.py

@@ -6,6 +6,7 @@
 
 import inspect
 import sys
+import os
 from importlib import import_module
 
 from makefun import add_signature_parameters, wraps
@@ -30,7 +31,7 @@
 from .common_others import get_function_host
 from .common_pytest_marks import make_marked_parameter_value, get_param_argnames_as_list, \
     get_pytest_parametrize_marks, get_pytest_usefixture_marks, PYTEST3_OR_GREATER, PYTEST6_OR_GREATER, \
-    PYTEST38_OR_GREATER, PYTEST34_OR_GREATER, PYTEST33_OR_GREATER
+    PYTEST38_OR_GREATER, PYTEST34_OR_GREATER, PYTEST33_OR_GREATER, PYTEST32_OR_GREATER
 from .common_pytest_lazy_values import is_lazy_value, is_lazy
 
 
@@ -65,6 +66,18 @@ def _decorate(f):
         return _decorate
 
 
+def pytest_is_running():
+    """Return True if the current process is a pytest run
+
+    See https://stackoverflow.com/questions/25188119/test-if-code-is-executed-from-within-a-py-test-session
+    """
+    if PYTEST32_OR_GREATER:
+        return "PYTEST_CURRENT_TEST" in os.environ
+    else:
+        import re
+        return any(re.findall(r'pytest|py.test', sys.argv[0]))
+
+
 def remove_duplicates(lst):
     dset = set()
     # relies on the fact that dset.add() always returns None.
@@ -619,7 +632,9 @@ def __init__(self, func):
 
         self.config = PYTEST_CONFIG
         if self.config is None:
-            raise ValueError("Internal error - config has not been correctly loaded. Please report")
+            # only raise if we are in pytest, otherwise silently skip
+            if pytest_is_running():
+                raise ValueError("Internal error - config has not been correctly loaded. Please report")
 
         self.function = func
         self.definition = MiniFuncDef(func.__name__)

pytest_cases/common_pytest_marks.py

@@ -29,6 +29,7 @@
 
 PYTEST_VERSION = LooseVersion(pytest.__version__)
 PYTEST3_OR_GREATER = PYTEST_VERSION >= LooseVersion('3.0.0')
+PYTEST32_OR_GREATER = PYTEST_VERSION >= LooseVersion('3.2.0')
 PYTEST33_OR_GREATER = PYTEST_VERSION >= LooseVersion('3.3.0')
 PYTEST34_OR_GREATER = PYTEST_VERSION >= LooseVersion('3.4.0')
 PYTEST35_OR_GREATER = PYTEST_VERSION >= LooseVersion('3.5.0')