1 files changed, 166 insertions, 0 deletions
diff --git a/lib/testtools/testtools/tests/test_monkey.py b/lib/testtools/testtools/tests/test_monkey.py
new file mode 100644
index 0000000000..09388b22f1
--- /dev/null
+++ b/lib/testtools/testtools/tests/test_monkey.py
@@ -0,0 +1,166 @@
+# Copyright (c) 2010 Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""Tests for testtools.monkey."""
+
+from testtools import TestCase
+from testtools.monkey import MonkeyPatcher, patch
+
+
+class TestObj:
+
+    def __init__(self):
+        self.foo = 'foo value'
+        self.bar = 'bar value'
+        self.baz = 'baz value'
+
+
+class MonkeyPatcherTest(TestCase):
+    """
+    Tests for 'MonkeyPatcher' monkey-patching class.
+    """
+
+    def setUp(self):
+        super(MonkeyPatcherTest, self).setUp()
+        self.test_object = TestObj()
+        self.original_object = TestObj()
+        self.monkey_patcher = MonkeyPatcher()
+
+    def test_empty(self):
+        # A monkey patcher without patches doesn't change a thing.
+        self.monkey_patcher.patch()
+
+        # We can't assert that all state is unchanged, but at least we can
+        # check our test object.
+        self.assertEquals(self.original_object.foo, self.test_object.foo)
+        self.assertEquals(self.original_object.bar, self.test_object.bar)
+        self.assertEquals(self.original_object.baz, self.test_object.baz)
+
+    def test_construct_with_patches(self):
+        # Constructing a 'MonkeyPatcher' with patches adds all of the given
+        # patches to the patch list.
+        patcher = MonkeyPatcher((self.test_object, 'foo', 'haha'),
+                                (self.test_object, 'bar', 'hehe'))
+        patcher.patch()
+        self.assertEquals('haha', self.test_object.foo)
+        self.assertEquals('hehe', self.test_object.bar)
+        self.assertEquals(self.original_object.baz, self.test_object.baz)
+
+    def test_patch_existing(self):
+        # Patching an attribute that exists sets it to the value defined in the
+        # patch.
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'haha')
+        self.monkey_patcher.patch()
+        self.assertEquals(self.test_object.foo, 'haha')
+
+    def test_patch_non_existing(self):
+        # Patching a non-existing attribute sets it to the value defined in
+        # the patch.
+        self.monkey_patcher.add_patch(self.test_object, 'doesntexist', 'value')
+        self.monkey_patcher.patch()
+        self.assertEquals(self.test_object.doesntexist, 'value')
+
+    def test_restore_non_existing(self):
+        # Restoring a value that didn't exist before the patch deletes the
+        # value.
+        self.monkey_patcher.add_patch(self.test_object, 'doesntexist', 'value')
+        self.monkey_patcher.patch()
+        self.monkey_patcher.restore()
+        marker = object()
+        self.assertIs(marker, getattr(self.test_object, 'doesntexist', marker))
+
+    def test_patch_already_patched(self):
+        # Adding a patch for an object and attribute that already have a patch
+        # overrides the existing patch.
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'blah')
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'BLAH')
+        self.monkey_patcher.patch()
+        self.assertEquals(self.test_object.foo, 'BLAH')
+        self.monkey_patcher.restore()
+        self.assertEquals(self.test_object.foo, self.original_object.foo)
+
+    def test_restore_twice_is_a_no_op(self):
+        # Restoring an already-restored monkey patch is a no-op.
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'blah')
+        self.monkey_patcher.patch()
+        self.monkey_patcher.restore()
+        self.assertEquals(self.test_object.foo, self.original_object.foo)
+        self.monkey_patcher.restore()
+        self.assertEquals(self.test_object.foo, self.original_object.foo)
+
+    def test_run_with_patches_decoration(self):
+        # run_with_patches runs the given callable, passing in all arguments
+        # and keyword arguments, and returns the return value of the callable.
+        log = []
+
+        def f(a, b, c=None):
+            log.append((a, b, c))
+            return 'foo'
+
+        result = self.monkey_patcher.run_with_patches(f, 1, 2, c=10)
+        self.assertEquals('foo', result)
+        self.assertEquals([(1, 2, 10)], log)
+
+    def test_repeated_run_with_patches(self):
+        # We can call the same function with run_with_patches more than
+        # once. All patches apply for each call.
+        def f():
+            return (self.test_object.foo, self.test_object.bar,
+                    self.test_object.baz)
+
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'haha')
+        result = self.monkey_patcher.run_with_patches(f)
+        self.assertEquals(
+            ('haha', self.original_object.bar, self.original_object.baz),
+            result)
+        result = self.monkey_patcher.run_with_patches(f)
+        self.assertEquals(
+            ('haha', self.original_object.bar, self.original_object.baz),
+            result)
+
+    def test_run_with_patches_restores(self):
+        # run_with_patches restores the original values after the function has
+        # executed.
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'haha')
+        self.assertEquals(self.original_object.foo, self.test_object.foo)
+        self.monkey_patcher.run_with_patches(lambda: None)
+        self.assertEquals(self.original_object.foo, self.test_object.foo)
+
+    def test_run_with_patches_restores_on_exception(self):
+        # run_with_patches restores the original values even when the function
+        # raises an exception.
+        def _():
+            self.assertEquals(self.test_object.foo, 'haha')
+            self.assertEquals(self.test_object.bar, 'blahblah')
+            raise RuntimeError, "Something went wrong!"
+
+        self.monkey_patcher.add_patch(self.test_object, 'foo', 'haha')
+        self.monkey_patcher.add_patch(self.test_object, 'bar', 'blahblah')
+
+        self.assertRaises(
+            RuntimeError, self.monkey_patcher.run_with_patches, _)
+        self.assertEquals(self.test_object.foo, self.original_object.foo)
+        self.assertEquals(self.test_object.bar, self.original_object.bar)
+
+
+class TestPatchHelper(TestCase):
+
+    def test_patch_patches(self):
+        # patch(obj, name, value) sets obj.name to value.
+        test_object = TestObj()
+        patch(test_object, 'foo', 42)
+        self.assertEqual(42, test_object.foo)
+
+    def test_patch_returns_cleanup(self):
+        # patch(obj, name, value) returns a nullary callable that restores obj
+        # to its original state when run.
+        test_object = TestObj()
+        original = test_object.foo
+        cleanup = patch(test_object, 'foo', 42)
+        cleanup()
+        self.assertEqual(original, test_object.foo)
+
+
+def test_suite():
+    from unittest import TestLoader
+    return TestLoader().loadTestsFromName(__name__)