Removes unused functions and test bag application to iterables.

tests/util/test_compat.py

@@ -0,0 +1,24 @@
+import pytest
+
+from bonobo.util.compat import deprecated, deprecated_alias
+
+
+def test_deprecated():
+    @deprecated
+    def foo():
+        pass
+
+    foo = deprecated(foo)
+    with pytest.warns(DeprecationWarning):
+        foo()
+
+
+def test_deprecated_alias():
+    def foo():
+        pass
+
+    foo = deprecated_alias('bar', foo)
+
+    with pytest.warns(DeprecationWarning):
+        foo()
+