feat(serializer): add support for FunctionType serialization

src/syrupy/extensions/amber/serializer.py

@@ -1,7 +1,9 @@
 import collections
+import inspect
 import os
 from collections import OrderedDict
 from types import (
+    FunctionType,
     GeneratorType,
     MappingProxyType,
 )
@@ -257,6 +259,8 @@ def _serialize(
             serialize_method = cls.serialize_namedtuple
         elif isinstance(data, (list, tuple, GeneratorType)):
             serialize_method = cls.serialize_iterable
+        elif isinstance(data, FunctionType):
+            serialize_method = cls.serialize_function
         return serialize_method(**serialize_kwargs)
 
     @classmethod
@@ -337,6 +341,14 @@ def serialize_dict(
             **kwargs,
         )
 
+    @classmethod
+    def serialize_function(
+        cls, data: FunctionType, *, depth: int = 0, **kwargs: Any
+    ) -> str:
+        return cls.__serialize_plain(
+            data=f"{data.__qualname__}{str(inspect.signature(data))}", depth=depth
+        )
+
     @classmethod
     def serialize_unknown(cls, data: Any, *, depth: int = 0, **kwargs: Any) -> str:
         if data.__class__.__repr__ != object.__repr__:

src/syrupy/extensions/json/__init__.py

@@ -1,7 +1,11 @@
 import datetime
+import inspect
 import json
 from collections import OrderedDict
-from types import GeneratorType
+from types import (
+    FunctionType,
+    GeneratorType,
+)
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -133,6 +137,12 @@ def _filter(
         if isinstance(data, (datetime.datetime,)):
             return data.strftime("%Y-%m-%dT%H:%M:%S.%f%z")
 
+        if isinstance(data, FunctionType):
+            return (
+                f"<{FunctionType.__name__} "
+                f"'{data.__qualname__}{str(inspect.signature(data))}'>"
+            )
+
         if data.__class__.__repr__ != object.__repr__:
             return repr(data)
 

tests/syrupy/extensions/amber/__snapshots__/test_amber_serializer.ambr

@@ -217,6 +217,12 @@
 # name: test_empty_snapshot.1
   ''
 # ---
+# name: test_function_in_file
+  "function_to_test(var1, var2='test_val', var3: str = 'test_val2', *, kwvar1, kwvar2='some_val') -> str"
+# ---
+# name: test_function_local
+  "test_function_local.<locals>.local_function_to_test(var1, var2='test_val', var3: str = 'test_val2', *, kwvar1, kwvar2='some_val') -> int"
+# ---
 # name: test_list[actual0]
   list([
   ])

tests/syrupy/extensions/amber/test_amber_serializer.py

@@ -233,3 +233,22 @@ def test_ordered_dict(snapshot):
 def test_many_sorted(snapshot):
     for i in range(25):
         assert i == snapshot
+
+
+def function_to_test(
+    var1, var2="test_val", var3: str = "test_val2", *, kwvar1, kwvar2="some_val"
+) -> str:
+    return "2"
+
+
+def test_function_in_file(snapshot):
+    assert snapshot() == function_to_test
+
+
+def test_function_local(snapshot):
+    def local_function_to_test(
+        var1, var2="test_val", var3: str = "test_val2", *, kwvar1, kwvar2="some_val"
+    ) -> int:
+        return 1
+
+    assert snapshot() == local_function_to_test

tests/syrupy/extensions/json/__snapshots__/test_json_serializer/test_function_in_file.json

@@ -0,0 +1 @@
+"<function 'function_to_test(var1, var2='test_val', var3: str = 'test_val2', *, kwvar1, kwvar2='some_val') -> str'>"

tests/syrupy/extensions/json/__snapshots__/test_json_serializer/test_function_local.json

@@ -0,0 +1 @@
+"<function 'test_function_local.<locals>.local_function_to_test(var1, var2='test_val', var3: str = 'test_val2', *, kwvar1, kwvar2='some_val') -> int'>"

tests/syrupy/extensions/json/test_json_serializer.py

@@ -232,3 +232,22 @@ def test_ordered_dict(snapshot_json):
     d["b"] = 0
     d["a"] = OrderedDict(b=True, a=False)
     assert snapshot_json == d
+
+
+def function_to_test(
+    var1, var2="test_val", var3: str = "test_val2", *, kwvar1, kwvar2="some_val"
+) -> str:
+    return "2"
+
+
+def test_function_in_file(snapshot_json):
+    assert snapshot_json() == function_to_test
+
+
+def test_function_local(snapshot_json):
+    def local_function_to_test(
+        var1, var2="test_val", var3: str = "test_val2", *, kwvar1, kwvar2="some_val"
+    ) -> int:
+        return 1
+
+    assert snapshot_json() == local_function_to_test