Merge lp:~mbp/testscenarios/658044-multiply into lp:~testtools-committers/testscenarios/trunk

[Martin Pool]

Adds similar facilities to https://code.edge.launchpad.net/~mbp/bzr/597791-http-tests/+merge/37941 in to testscenarios

[Robert Collins (lifeless)]

tsk, naughty poolie - tests fail.

Also README is a doctest, so I'll just update, fix and merge.

review: Approve

[Martin Pool (mbp)]

Thanks.

[Robert Collins (lifeless)]

Also python works quite well with nouns as variable names rather than single letters :P

=== modified file 'README'
--- README	2009-12-19 03:09:14 +0000
+++ README	2010-10-12 05:03:45 +0000
@@ -128,6 +128,19 @@
   ...     result.addTests(generate_scenarios(standard_tests))
   ...     return result
 
+as a convenience, this is available in ``load_tests_apply_scenarios``, so a
+module using scenario tests need only say ::
+
+    from testscenarios import load_tests_apply_scenarios
+
+    load_tests = load_tests_apply_scenarios
+
+It's suggested for clarity this be done near the top of the file.
+
+Python 2.7 and greater support a different calling convention for `load_tests``
+<https://bugs.launchpad.net/bzr/+bug/607412>.  `load_tests_apply_scenarios`
+copes with both.
+
 With ``test_suite``::
 
   >>> def test_suite():
@@ -254,3 +267,16 @@
 
 If a parameterised test is because of a bug run without being parameterized,
 it should fail rather than running with defaults, because this can hide bugs.
+
+
+Producing Scenarios
+===================
+
+The `multiply_scenarios` function produces the cross-product of the scenarios
+passed in::
+
+    scenarios = multiply_scenarios(
+	vary_by_http_client(),
+	vary_by_http_protocol_version(),
+	)
+  

=== modified file 'lib/testscenarios/scenarios.py'
--- lib/testscenarios/scenarios.py	2010-02-01 04:49:05 +0000
+++ lib/testscenarios/scenarios.py	2010-10-12 05:03:45 +0000
@@ -2,6 +2,7 @@
 #  dependency injection ('scenarios') by tests.
 #
 # Copyright (c) 2009, Robert Collins <[e-mail]>
+# Copyright (c) 2010 Martin Pool <[e-mail]>
 # 
 # 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
@@ -18,8 +19,14 @@
     'apply_scenario',
     'apply_scenarios',
     'generate_scenarios',
+    'load_tests_apply_scenarios',
     ]
 
+
+from itertools import (
+    chain,
+    product,
+    )
 import unittest
 
 from testtools.testcase import clone_test_with_new_id
@@ -76,3 +83,49 @@
                 yield newtest
         else:
             yield test
+
+
+def load_tests_apply_scenarios(*params):
+    """Multiply out all tests in a module that have scenarios.
+
+    If this is referenced by the `load_tests` attribute of a module, then
+    testloaders that implement this protocol will automatically arrange for
+    the scenarios to be expanded.  In this case it is not necessary (or
+    desirable) to subclass TestWithScenarios.
+
+    Two different calling conventions for load_tests have been used, and this
+    function should support both.  Python 2.7 passes (loader, standard_tests,
+    pattern), and bzr, nose and others have used (standard_tests,
+    module, loader).  See <http://pad.lv/607412>.
+
+    :param loader: A TestLoader.
+    :param standard_test: The test objects found in this module before 
+        multiplication.
+    """
+    if getattr(params[0], 'suiteClass', None) is not None:
+        loader, standard_tests, pattern = params
+    else:
+        standard_tests, module, loader = params
+    result = loader.suiteClass()
+    result.addTests(generate_scenarios(standard_tests))
+    return result
+
+
+def multiply_scenarios(*scenarios):
+    """Multiply two or more iterables of scenarios.
+
+    It is safe to pass scenario generators or iterators.
+
+    :returns: A list of compound scenarios: the cross-product of all 
+        scenarios, with the names concatenated and the parameters
+        merged together.
+    """
+    r = []
+    scenario_lists = map(list, scenarios)
+    products = product(*scenario_lists)
+    for combo in products:
+        names, params = zip(*combo)
+        for p in params:
+            d.update(p.iteritems())
+        r.append((','.join(names), d))
+    return r

=== modified file 'lib/testscenarios/tests/test_scenarios.py'
--- lib/testscenarios/tests/test_scenarios.py	2010-02-01 04:49:05 +0000
+++ lib/testscenarios/tests/test_scenarios.py	2010-10-12 05:03:45 +0000
@@ -2,6 +2,7 @@
 #  dependency injection ('scenarios') by tests.
 #
 # Copyright (c) 2009, Robert Collins <[e-mail]>
+# Copyright (c) 2010 Martin Pool <[e-mail]>
 # 
 # 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
@@ -21,6 +22,8 @@
     apply_scenario,
     apply_scenarios,
     generate_scenarios,
+    load_tests_apply_scenarios,
+    multiply_scenarios,
     )
 import testtools
 from testtools.tests.helpers import LoggingResult
@@ -171,3 +174,70 @@
         tests = list(apply_scenarios(ReferenceTest.scenarios, test))
         self.assertEqual([('demo', {})], ReferenceTest.scenarios)
         self.assertEqual(ReferenceTest.scenarios, tests[0].scenarios)
+
+
+class TestLoadTests(testtools.TestCase):
+
+    class SampleTest(unittest.TestCase):
+        def test_nothing(self): 
+            pass
+        scenarios = [
+            ('a', {}),
+            ('b', {}),
+            ]
+
+    def test_load_tests_apply_scenarios(self):
+        suite = load_tests_apply_scenarios(
+            unittest.TestLoader(),
+            [self.SampleTest('test_nothing')],
+            None)
+        result_tests = list(testtools.iterate_tests(suite))
+        self.assertEquals(
+            2,
+            len(result_tests),
+            result_tests)
+
+    def test_load_tests_apply_scenarios_old_style(self):
+        """Call load_tests in the way used by pre-Python2.7 code.
+
+        See <https://bugs.launchpad.net/bzr/+bug/607412>
+        """
+        suite = load_tests_apply_scenarios(
+            [self.SampleTest('test_nothing')],
+            self.__class__.__module__,
+            unittest.TestLoader(),
+            )
+        result_tests = list(testtools.iterate_tests(suite))
+        self.assertEquals(
+            2,
+            len(result_tests),
+            result_tests)
+
+
+class TestMultiplyScenarios(testtools.TestCase):
+
+    def test_multiply_scenarios(self):
+        def s(name):
+            for i in 'ab':
+                yield i, {name: i}
+        r = list(multiply_scenarios(s('p'), s('q')))
+        self.assertEquals([
+            ('a,a', dict(p='a', q='a')),
+            ('a,b', dict(p='a', q='b')),
+            ('b,a', dict(p='b', q='a')),
+            ('b,b', dict(p='b', q='b')),
+            ],
+            r)
+
+    def test_multiply_many_scenarios(self):
+        def s(name):
+            for i in 'abc':
+                yield i, {name: i}
+        r = list(multiply_scenarios(s('p'), s('q'), s('r'), s('t')))
+        self.assertEqual(
+            3**4,
+            len(r),
+            r)
+        self.assertEqual(
+            'a,a,a,a',
+            r[0][0])