Add deprecation tests

Author: Ben Cipollini

nibabel/tests/test_checkwarns.py

@@ -2,8 +2,25 @@
 """
 from __future__ import division, print_function, absolute_import
 
-from ..checkwarns import ErrorWarnings, IgnoreWarnings
-
 from nose.tools import assert_true, assert_equal, assert_raises
 from ..testing import (error_warnings, suppress_warnings,
                        clear_and_catch_warnings)
+
+
+def test_ignore_and_error_warnings():
+    with clear_and_catch_warnings() as w:
+        from ..checkwarns import ErrorWarnings, IgnoreWarnings
+        assert_equal(len(w), 1)
+        assert_equal(w[0].category, FutureWarning)
+
+    with clear_and_catch_warnings() as w:
+        with IgnoreWarnings():
+            pass
+        assert_equal(len(w), 1)
+        assert_equal(w[0].category, FutureWarning)
+
+    with clear_and_catch_warnings() as w:
+        with ErrorWarnings():
+            pass
+        assert_equal(len(w), 1)
+        assert_equal(w[0].category, FutureWarning)

nibabel/tests/test_testing.py

@@ -60,6 +60,45 @@ def test_assert_allclose_safely():
     assert_allclose_safely([], [])
 
 
+def test_clear_and_catch_warnings():
+    # Initial state of module, no warnings
+    my_mod = _get_fresh_mod()
+    assert_equal(getattr(my_mod, '__warningregistry__', {}), {})
+    with clear_and_catch_warnings(modules=[my_mod]):
+        warnings.simplefilter('ignore')
+        warnings.warn('Some warning')
+    assert_equal(my_mod.__warningregistry__, {})
+    # Without specified modules, don't clear warnings during context
+    with clear_and_catch_warnings():
+        warnings.simplefilter('ignore')
+        warnings.warn('Some warning')
+    assert_warn_len_equal(my_mod, 1)
+    # Confirm that specifying module keeps old warning, does not add new
+    with clear_and_catch_warnings(modules=[my_mod]):
+        warnings.simplefilter('ignore')
+        warnings.warn('Another warning')
+    assert_warn_len_equal(my_mod, 1)
+    # Another warning, no module spec does add to warnings dict, except on
+    # Python 3.4 (see comments in `assert_warn_len_equal`)
+    with clear_and_catch_warnings():
+        warnings.simplefilter('ignore')
+        warnings.warn('Another warning')
+    assert_warn_len_equal(my_mod, 2)
+
+
+class my_cacw(clear_and_catch_warnings):
+    class_modules = (sys.modules[__name__],)
+
+
+def test_clear_and_catch_warnings_inherit():
+    # Test can subclass and add default modules
+    my_mod = _get_fresh_mod()
+    with my_cacw():
+        warnings.simplefilter('ignore')
+        warnings.warn('Some warning')
+    assert_equal(my_mod.__warningregistry__, {})
+
+
 def test_warn_error():
     # Check warning error context manager
     n_warns = len(filters)