fix: compare snapshots without deserializing (#26)

* wip: remove deserialization

* wip: use yaml safe full loader

* wip: compare serialized data

* wip: remove unneeded import

* test: refactor grouping

* refactor: test grouping

* wip: do not rewrite matching snapshots

* cr: collapse conditionals

Author: iamogbz

src/syrupy/assertion.py

@@ -66,12 +66,13 @@ def assert_match(self, data):
         assert self == data
 
     def get_assert_diff(self, data) -> List[str]:
-        deserialized = self._recall_data(index=self.num_executions - 1)
-        if deserialized is None:
+        serialized_data = self.serializer.encode(data)
+        snapshot_data = self._recall_data(index=self.num_executions - 1)
+        if snapshot_data is None:
             return ["Snapshot does not exist!"]
 
-        if data != deserialized:
-            return [f"- {data}", f"+ {deserialized}"]
+        if serialized_data != snapshot_data:
+            return [f"- {serialized_data}", f"+ {snapshot_data}"]
 
         return []
 
@@ -90,23 +91,20 @@ def __eq__(self, other) -> bool:
     def _assert(self, data) -> bool:
         self._session.register_assertion(self)
         try:
-            if self._update_snapshots:
-                serialized_data = self.serializer.encode(data)
+            serialized_data = self.serializer.encode(data)
+            snapshot_data = self._recall_data(index=self.num_executions)
+            matches = snapshot_data is not None and serialized_data == snapshot_data
+            if not matches and self._update_snapshots:
                 self.io.create_or_update_snapshot(
                     serialized_data, index=self.num_executions
                 )
                 return True
-
-            deserialized = self._recall_data(index=self.num_executions)
-            if deserialized is None or data != deserialized:
-                return False
-            return True
+            return matches
         finally:
             self._executions += 1
 
     def _recall_data(self, index: int) -> Optional[Any]:
         try:
-            saved_data = self.io.read_snapshot(index=index)
-            return self.serializer.decode(saved_data)
+            return self.io.read_snapshot(index=index)
         except SnapshotDoesNotExist:
             return None

src/syrupy/io.py

@@ -128,7 +128,7 @@ def _read_file(self, filepath: str) -> Any:
         """
         try:
             with open(filepath, "r") as f:
-                return yaml.safe_load(f) or {}
+                return yaml.load(f, Loader=yaml.FullLoader) or {}
         except FileNotFoundError:
             pass
         return {}
@@ -158,7 +158,7 @@ def _write_file(self, filepath: str, data: Any):
         Writes the snapshot data into the snapshot file that be read later.
         """
         with open(filepath, "w") as f:
-            yaml.safe_dump(data, f)
+            yaml.dump(data, f, allow_unicode=True)
 
     def _snap_file_hook(self, index: int):
         """

src/syrupy/serializer.py

@@ -7,6 +7,3 @@ def __init__(self):
 
     def encode(self, data):
         return data
-
-    def decode(self, data):
-        return data

tests/__snapshots__/test_snapshots.yaml

@@ -28,5 +28,36 @@ test_parametrized_with_special_char[Escaped \\n]:
   data: Escaped \n
 test_raw_string:
   data: Raw string
+test_set:
+  data: !!set
+    a: null
+    is: null
+    set: null
+    this: null
+test_set.1:
+  data: !!set
+    this: null
+    is: null
+    a: null
+    ? !!python/object/apply:builtins.frozenset
+    - - nested, set
+    : null
 test_simple_string:
   data: Loreeeeeem ipsum.
+test_tuples:
+  data: !!python/tuple
+  - this
+  - is
+  - !!python/tuple
+    - a
+    - tuple
+test_tuples.1:
+  data: !!python/object/new:tests.test_snapshots.ExampleTuple
+  - this
+  - is
+  - a
+  - !!set
+    named: null
+    tuple: null
+test_unicode_string:
+  data: 🥞🐍🍯

tests/test_snapshots.py

@@ -1,3 +1,4 @@
+from collections import namedtuple
 import pytest
 
 
@@ -9,6 +10,10 @@ def test_raw_string(snapshot):
     assert r"Raw string" == snapshot
 
 
+def test_unicode_string(snapshot):
+    assert "🥞🐍🍯" == snapshot
+
+
 def test_multiple_snapshots(snapshot):
     assert "First." == snapshot
     snapshot.assert_match("Second.")
@@ -29,3 +34,16 @@ def test_parametrized_with_special_char(snapshot, expected):
 )
 def test_dict(snapshot, actual):
     assert actual == snapshot
+
+
+def test_set(snapshot):
+    assert snapshot == {"this", "is", "a", "set"}
+    assert snapshot == {"this", "is", "a", frozenset({"nested, set"})}
+
+
+ExampleTuple = namedtuple("ExampleTuple", ["a", "b", "c", "d"])
+
+
+def test_tuples(snapshot):
+    assert snapshot == ("this", "is", ("a", "tuple"))
+    assert snapshot == ExampleTuple(a="this", b="is", c="a", d={"named", "tuple"})