Test the popitem method of MutableMappings too (zarr-developers#378)

jakirkham · web-flow · commit 585f0f51c697 · 2019-01-15T20:08:57.000-05:00
Adds a test for the `popitem` method of `MutableMapping`'s as well.
Typically this is not used, but it does get used in the default `clear`
method. Given this method doesn't guarantee an order, use a store with a
single-key value pair to simplify the test logic. Also test the case of
an empty store to make sure it errors out properly. Override the
`popitem` method appropriate for stores that do not handle removal
properly.
diff --git a/zarr/tests/test_storage.py b/zarr/tests/test_storage.py
@@ -93,6 +93,16 @@ def test_pop(self):
         with pytest.raises(KeyError):
             store.pop('xxx')
 
+    def test_popitem(self):
+        store = self.create_store()
+        store['foo'] = b'bar'
+        k, v = store.popitem()
+        assert k == 'foo'
+        assert v == b'bar'
+        assert len(store) == 0
+        with pytest.raises(KeyError):
+            store.popitem()
+
     def test_writeable_values(self):
         store = self.create_store()
 
@@ -762,6 +772,13 @@ def test_pop(self):
         with pytest.raises(NotImplementedError):
             store.pop('foo')
 
+    def test_popitem(self):
+        # override because not implemented
+        store = self.create_store()
+        store['foo'] = b'bar'
+        with pytest.raises(NotImplementedError):
+            store.popitem()
+
 
 class TestDBMStore(StoreTests, unittest.TestCase):
 
