diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 41a7cd6..38eecac 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,7 +11,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v2
+        uses: MatteoH2O1999/setup-python@v0.1.1
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
diff --git a/mockfirestore/document.py b/mockfirestore/document.py
index 24aa433..2fc4c92 100644
--- a/mockfirestore/document.py
+++ b/mockfirestore/document.py
@@ -77,6 +77,17 @@ def set(self, data: Dict, merge=False):
                 self.set(data)
         else:
             set_by_path(self._data, self._path, deepcopy(data))
+            
+    def __hash__(self):
+        return hash(tuple(self._path))
+
+    def __eq__(self, other):
+        if not isinstance(other, self.__class__):
+            return False
+
+        return self._path == other._path
+
+
 
     def update(self, data: Dict[str, Any]):
         document = get_by_path(self._data, self._path)
diff --git a/tests/test_collection_reference.py b/tests/test_collection_reference.py
index 7f1924a..e4dcc30 100644
--- a/tests/test_collection_reference.py
+++ b/tests/test_collection_reference.py
@@ -193,6 +193,19 @@ def test_collection_whereArrayContainsAny(self):
         self.assertEqual({'field': ['val4']}, contains_any_docs[0].to_dict())
         self.assertEqual({'field': ['val3', 'val2', 'val1']}, contains_any_docs[1].to_dict())
 
+    def test_collection_whereByReference(self):
+        fs = MockFirestore()
+        fs._data = {
+        'foo': {
+            'otherDocRef': {'ref': fs.document('bar/first')},
+        }}
+
+        doc_ref = fs.collection('bar').document('first')
+
+        docs = list(fs.collection('foo').where('ref', '==', doc_ref).stream())
+        self.assertEqual(len(docs), 1)
+        self.assertEqual({'ref': fs.document('bar/first')}, docs[0].to_dict())
+
     def test_collection_orderBy(self):
         fs = MockFirestore()
         fs._data = {'foo': {