feat: implement binary selfie methods in Python (#496)

Author: nedtwigg

python/example-pytest-selfie/tests/binary_test.py

@@ -0,0 +1,73 @@
+import pytest
+from selfie_lib import expect_selfie
+
+
+def test_empty_binary_base64():
+    """Test base64 encoding of empty byte array"""
+    expect_selfie(bytes()).to_be_base64("")
+
+
+def test_large_binary_base64():
+    """Test base64 encoding of large byte array (256 bytes)"""
+    data = bytes(range(256))
+    expect_selfie(data).to_be_base64(
+        "AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4vMDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5fYGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6PkJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/w=="
+    )
+
+
+def test_binary_file():
+    """Test writing binary data to a file"""
+    data = b"test binary data"
+    expect_selfie(data).to_be_file("tests/binary_test__test_binary_file.bin")
+
+
+def test_binary_file_duplicate_equal():
+    """Test writing same binary data to a file multiple times"""
+    expect_selfie(b"equal").to_be_file(
+        "tests/binary_test__test_binary_file_duplicate_equal.bin"
+    )
+    expect_selfie(b"equal").to_be_file(
+        "tests/binary_test__test_binary_file_duplicate_equal.bin"
+    )
+
+
+def test_binary_file_duplicate_unequal():
+    """Test writing same binary data to a file multiple times"""
+    with pytest.raises(Exception) as exc_info:
+        expect_selfie(b"a").to_be_file(
+            "tests/binary_test__test_binary_file_duplicate_unequal.bin"
+        )
+        expect_selfie(b"b").to_be_file(
+            "tests/binary_test__test_binary_file_duplicate_unequal.bin"
+        )
+    expect_selfie(safify(str(exc_info.value))).to_be(
+        "Snapshot mismatch, TODO: string comparison"
+    )
+
+
+def test_binary_file_mismatch():
+    """Test error handling for mismatched binary data"""
+    with pytest.raises(AssertionError):
+        expect_selfie(b"different").to_be_file(
+            "tests/binary_test__SHOULD_NOT_EXIST.bin"
+        )
+
+
+def test_binary_file_not_found():
+    """Test error handling for non-existent file"""
+    with pytest.raises(AssertionError) as exc_info:
+        expect_selfie(b"test").to_be_file("tests/binary_test__SHOULD_NOT_EXIST.bin")
+    assert "no such file" in str(exc_info.value)
+
+
+def test_base64_mismatch():
+    """Test error handling for mismatched base64 data"""
+    with pytest.raises(Exception) as exc_info:
+        expect_selfie(b"test data").to_be_base64("AAAA")
+    expect_selfie(safify(str(exc_info.value))).to_be(
+        "Snapshot mismatch, TODO: string comparison"
+    )
+
+
+def safify(string: str) -> str:
+    return string.split("\n")[0]

python/example-pytest-selfie/tests/binary_test__test_binary_file.bin

@@ -0,0 +1 @@
+test binary data

python/example-pytest-selfie/tests/binary_test__test_binary_file_duplicate_equal.bin

@@ -0,0 +1 @@
+equal

python/example-pytest-selfie/tests/binary_test__test_binary_file_duplicate_unequal.bin

@@ -0,0 +1 @@
+a

python/example-pytest-selfie/tests/to_be_file_test.py

@@ -56,7 +56,7 @@ def __nullable_to_string(self, value, on_null: str) -> str:
     def __comparison_assertion(
         self, message: str, expected: str, actual: str
     ) -> Exception:
-        # this *should* through an exception that a good pytest runner will show nicely
+        # this *should* throw an exception that a good pytest runner will show nicely
         assert expected == actual, message
         # but in case it doesn't, we'll create our own here
         return AssertionError(message)
@@ -69,6 +69,9 @@ def __init__(self, fs: FSImplementation, settings: SelfieSettingsAPI):
         self.__root_folder = TypedPath.of_folder(os.path.abspath(settings.root_dir))
         self.unix_newlines = self.__infer_default_line_ending_is_unix()
 
+    def root_folder(self) -> TypedPath:
+        return self.__root_folder
+
     def snapshotfile_for_testfile(self, testfile: TypedPath) -> TypedPath:
         if testfile.name.endswith(".py"):
             return testfile.parent_folder().resolve_file(f"{testfile.name[:-3]}.ss")

python/example-pytest-selfie/uv.lock

@@ -81,7 +81,7 @@ def to_match_disk_TODO(self, sub: str = "") -> "DiskSelfie":
             return self
         else:
             raise _selfieSystem().fs.assert_failed(
-                f"Can't call `toMatchDisk_TODO` in {Mode.readonly} mode!"
+                message=f"Can't call `toMatchDisk_TODO` in {Mode.readonly} mode!"
             )
 
     def facet(self, facet: str) -> "StringFacet":
@@ -186,17 +186,71 @@ def __init__(self, actual: Snapshot, disk: DiskStorage, only_facet: str):
                 f"The facet {only_facet} is a string, not a binary snapshot"
             )
 
-    def to_be_base64(self, expected: str) -> bytes:
-        raise NotImplementedError
+    def _actual_bytes(self) -> bytes:
+        return self.actual.subject_or_facet(self.only_facet).value_binary()
+
+    def to_match_disk(self, sub: str = "") -> "BinarySelfie":
+        super().to_match_disk(sub)
+        return self
+
+    def to_match_disk_TODO(self, sub: str = "") -> "BinarySelfie":
+        super().to_match_disk_TODO(sub)
+        return self
 
     def to_be_base64_TODO(self, _: Any = None) -> bytes:
-        raise NotImplementedError
+        _toBeDidntMatch(None, self._actual_string(), LiteralString())
+        return self._actual_bytes()
 
-    def to_be_file(self, subpath: str) -> bytes:
-        raise NotImplementedError
+    def to_be_base64(self, expected: str) -> bytes:
+        expected_bytes = base64.b64decode(expected)
+        actual_bytes = self._actual_bytes()
+        if actual_bytes == expected_bytes:
+            return _checkSrc(actual_bytes)
+        else:
+            _toBeDidntMatch(expected, self._actual_string(), LiteralString())
+            return actual_bytes
+
+    def _actual_string(self) -> str:
+        return base64.b64encode(self._actual_bytes()).decode().replace("\r", "")
+
+    def _to_be_file_impl(self, subpath: str, is_todo: bool) -> bytes:
+        call = recordCall(False)
+        writable = _selfieSystem().mode.can_write(is_todo, call, _selfieSystem())
+        actual_bytes = self._actual_bytes()
+        path = _selfieSystem().layout.root_folder().resolve_file(subpath)
+
+        if writable:
+            if is_todo:
+                _selfieSystem().write_inline(TodoStub.to_be_file.create_literal(), call)
+            _selfieSystem().write_to_be_file(path, actual_bytes, call)
+            return actual_bytes
+        else:
+            if is_todo:
+                raise _selfieSystem().fs.assert_failed(
+                    f"Can't call `to_be_file_TODO` in {Mode.readonly} mode!"
+                )
+            else:
+                if not _selfieSystem().fs.file_exists(path):
+                    raise _selfieSystem().fs.assert_failed(
+                        _selfieSystem().mode.msg_snapshot_not_found_no_such_file(path)
+                    )
+                expected = _selfieSystem().fs.file_read_binary(path)
+                if expected == actual_bytes:
+                    return actual_bytes
+                else:
+                    raise _selfieSystem().fs.assert_failed(
+                        message=_selfieSystem().mode.msg_snapshot_mismatch_binary(
+                            expected, actual_bytes
+                        ),
+                        expected=expected,
+                        actual=actual_bytes,
+                    )
 
     def to_be_file_TODO(self, subpath: str) -> bytes:
-        raise NotImplementedError
+        return self._to_be_file_impl(subpath, True)
+
+    def to_be_file(self, subpath: str) -> bytes:
+        return self._to_be_file_impl(subpath, False)
 
 
 def _checkSrc(value: T) -> T:
@@ -216,16 +270,27 @@ def _toBeDidntMatch(expected: Optional[T], actual: T, fmt: LiteralFormat[T]) ->
                 f"Can't call `toBe_TODO` in {Mode.readonly} mode!"
             )
         else:
-            raise _selfieSystem().fs.assert_failed(
-                _selfieSystem().mode.msg_snapshot_mismatch(), expected, actual
-            )
+            expectedStr = repr(expected)
+            actualStr = repr(actual)
+            if expectedStr == actualStr:
+                raise ValueError(
+                    f"Value of type {type(actual)} is not `==` to the expected value, but they both have the same `repr` value:\n${expectedStr}"
+                )
+            else:
+                raise _selfieSystem().fs.assert_failed(
+                    message=_selfieSystem().mode.msg_snapshot_mismatch(
+                        expected=expectedStr, actual=actualStr
+                    ),
+                    expected=expected,
+                    actual=actual,
+                )
 
 
 def _assertEqual(
     expected: Optional[Snapshot], actual: Snapshot, storage: SnapshotSystem
 ):
     if expected is None:
-        raise storage.fs.assert_failed(storage.mode.msg_snapshot_not_found())
+        raise storage.fs.assert_failed(message=storage.mode.msg_snapshot_not_found())
     elif expected == actual:
         return
     else:
@@ -240,10 +305,14 @@ def _assertEqual(
                 ),
             )
         )
+        expectedFacets = _serializeOnlyFacets(expected, mismatched_keys)
+        actualFacets = _serializeOnlyFacets(actual, mismatched_keys)
         raise storage.fs.assert_failed(
-            storage.mode.msg_snapshot_mismatch(),
-            _serializeOnlyFacets(expected, mismatched_keys),
-            _serializeOnlyFacets(actual, mismatched_keys),
+            message=storage.mode.msg_snapshot_mismatch(
+                expected=expectedFacets, actual=actualFacets
+            ),
+            expected=expectedFacets,
+            actual=actualFacets,
         )