FEAT: Add DontCare for Easy Testing

keg_elements/testing.py

@@ -11,6 +11,23 @@
 ColumnCheck.__new__.__defaults__ = (True, None, None, None)
 
 
+class DontCare(object):  # pragma: no cover
+    """A placeholder object that can conform to almost anything and is always
+    equal to anything it is compared against.
+
+    Examples:
+
+        assert [1, 2, 3] == [1, DontCare(), 3]
+    """
+    __eq__ = lambda *_: True
+    __ne__ = lambda *_: False
+    __repr__ = lambda *_: '_'
+
+    __getattr__ = lambda *_: DontCare()
+    __getitem__ = lambda *_: DontCare()
+    __call__ = lambda *a, **kw: DontCare()
+
+
 class EntityBase(object):
     entity_cls = None
     column_checks = None

keg_elements/tests/test_testing.py

@@ -0,0 +1,12 @@
+import keg_elements.testing as testing
+
+
+def test_dont_care():
+    assert testing.DontCare() == True  # noqa
+    assert (testing.DontCare() == True) is True  # noqa
+    assert (testing.DontCare() == False) is True  # noqa
+    assert (testing.DontCare() == object) is True  # noqa
+    assert (testing.DontCare() != object) is False  # noqa
+    assert (testing.DontCare()() == object) is True  # noqa
+    assert (testing.DontCare()['thing'] == object) is True  # noqa
+    assert (testing.DontCare()[1] == object) is True  # noqa