lib.util.Namespace raises the expected exception

package/MDAnalysis/lib/util.py

@@ -1331,29 +1331,30 @@ def blocks_of(a, n, m):
 
     return np.lib.stride_tricks.as_strided(a, new_shape, new_strides)
 
-class Namespace(object):
+class Namespace(dict):
     """Class to allow storing attributes in new namespace. """
     def __getattr__(self, key):
         # a.this causes a __getattr__ call for key = 'this'
-        return self.__dict__[key]
+        try:
+            return dict.__getitem__(self, key)
+        except KeyError:
+            raise AttributeError('"{}" is not known in the namespace.'
+                                 .format(key))
+
     def __setattr__(self, key, value):
-        # a.this = 10 causes a __setattr__ call for key='this' value=10
-        self.__dict__[key] = value
+        dict.__setitem__(self, key, value)
+
     def __delattr__(self, key):
-        del self.__dict__[key]
+        try:
+            dict.__delitem__(self, key)
+        except KeyError:
+            raise AttributeError('"{}" is not known in the namespace.'
+                                 .format(key))
+
     def __eq__(self, other):
         try:
             # this'll allow us to compare if we're storing arrays
-            assert_equal(self.__dict__, other.__dict__)
+            assert_equal(self, other)
         except AssertionError:
             return False
         return True
-    def __str__(self):
-        return str(self.__dict__)
-    def __len__(self):
-        return len(self.__dict__)
-    def __getitem__(self, key):
-        return self.__dict__[key]
-    def __iter__(self):
-        for i in self.__dict__:
-            yield i

testsuite/MDAnalysisTests/coordinates/base.py

@@ -293,7 +293,7 @@ def test_add_same_auxname_raises_ValueError(self):
     def test_remove_auxiliary(self):
         self.reader.remove_auxiliary('lowf')
         assert_raises(AttributeError, getattr, self.reader._auxs, 'lowf')
-        assert_raises(KeyError, getattr, self.reader.ts.aux, 'lowf')
+        assert_raises(AttributeError, getattr, self.reader.ts.aux, 'lowf')
 
     @raises(ValueError)
     def test_remove_nonexistant_auxiliary_raises_ValueError(self):
@@ -344,7 +344,7 @@ def test_rename_aux(self):
         assert_equal(self.reader.ts.aux.lowf_renamed,
                      self.ref.aux_lowf_data[0])
         # old name should be removed
-        assert_raises(KeyError, getattr, self.reader.ts.aux, 'lowf')
+        assert_raises(AttributeError, getattr, self.reader.ts.aux, 'lowf')
         # new name should be retained
         next(self.reader)
         assert_equal(self.reader.ts.aux.lowf_renamed,

testsuite/MDAnalysisTests/test_util.py → testsuite/MDAnalysisTests/lib/test_util.py

@@ -819,3 +819,80 @@ def test_blocks_of_VE(self):
         arr = np.arange(16).reshape(4, 4)
 
         assert_raises(ValueError, util.blocks_of, arr, 2, 1)
+
+
+class TestNamespace(object):
+    def setUp(self):
+        self.ns = util.Namespace()
+
+    def tearDown(self):
+        del self.ns
+
+    def test_getitem(self):
+        self.ns.this = 42
+
+        assert_(self.ns['this'] == 42)
+
+    def test_getitem_KE(self):
+        assert_raises(KeyError, dict.__getitem__, self.ns, 'this')
+
+    def test_setitem(self):
+        self.ns['this'] = 42
+
+        assert_(self.ns['this'] == 42)
+
+    def test_delitem(self):
+        self.ns['this'] = 42
+        assert_('this' in self.ns)
+        del self.ns['this']
+        assert_(not ('this' in self.ns))
+
+    def test_delitem_AE(self):
+        def deller():
+            del self.ns.this
+        assert_raises(AttributeError, deller)
+
+    def test_setattr(self):
+        self.ns.this = 42
+
+        assert_(self.ns.this == 42)
+
+    def test_getattr(self):
+        self.ns['this'] = 42
+
+        assert_(self.ns.this == 42)
+
+    def test_getattr_AE(self):
+        assert_raises(AttributeError, getattr, self.ns, 'this')
+
+    def test_delattr(self):
+        self.ns['this'] = 42
+
+        assert_('this' in self.ns)
+        del self.ns.this
+        assert_(not ('this' in self.ns))
+
+    def test_eq(self):
+        self.ns['this'] = 42
+
+        ns2 = util.Namespace()
+        ns2['this'] = 42
+
+        assert_(self.ns == ns2)
+
+    def test_len(self):
+        assert_(len(self.ns) == 0)
+        self.ns['this'] = 1
+        self.ns['that'] = 2
+        assert_(len(self.ns) == 2)
+
+    def test_iter(self):
+        self.ns['this'] = 12
+        self.ns['that'] = 24
+        self.ns['other'] = 48
+
+        seen = []
+        for val in self.ns:
+            seen.append(val)
+        for val in ['this', 'that', 'other']:
+            assert_(val in seen)