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-rw-r--r--lib/testscenarios/scenarios.py37
1 files changed, 36 insertions, 1 deletions
diff --git a/lib/testscenarios/scenarios.py b/lib/testscenarios/scenarios.py
index 80847d6..9538b33 100644
--- a/lib/testscenarios/scenarios.py
+++ b/lib/testscenarios/scenarios.py
@@ -2,7 +2,7 @@
# dependency injection ('scenarios') by tests.
#
# Copyright (c) 2009, Robert Collins <robertc@robertcollins.net>
-# Copyright (c) 2010 Martin Pool <mbp@sourcefrog.net>
+# Copyright (c) 2010, 2011 Martin Pool <mbp@sourcefrog.net>
#
# Licensed under either the Apache License, Version 2.0 or the BSD 3-clause
# license at the users choice. A copy of both licenses are available in the
@@ -27,6 +27,7 @@ from itertools import (
chain,
product,
)
+import sys
import unittest
from testtools.testcase import clone_test_with_new_id
@@ -129,3 +130,37 @@ def multiply_scenarios(*scenarios):
scenario_parameters.update(parameter)
result.append((scenario_name, scenario_parameters))
return result
+
+
+def per_module_scenarios(attribute_name, modules):
+ """Generate scenarios for available implementation modules.
+
+ This is typically used when there is a subsystem implemented, for
+ example, in both Python and C, and we want to apply the same tests to
+ both, but the C module may sometimes not be available.
+
+ Note: if the module can't be loaded, the sys.exc_info() tuple for the
+ exception raised during import of the module is used instead of the module
+ object. A common idiom is to check in setUp for that and raise a skip or
+ error for that case. No special helpers are supplied in testscenarios as
+ yet.
+
+ :param attribute_name: A name to be set in the scenario parameter
+ dictionary (and thence onto the test instance) pointing to the
+ implementation module (or import exception) for this scenario.
+
+ :param modules: An iterable of (short_name, module_name), where
+ the short name is something like 'python' to put in the
+ scenario name, and the long name is a fully-qualified Python module
+ name.
+ """
+ scenarios = []
+ for short_name, module_name in modules:
+ try:
+ mod = __import__(module_name, {}, {}, [''])
+ except:
+ mod = sys.exc_info()
+ scenarios.append((
+ short_name,
+ {attribute_name: mod}))
+ return scenarios