Improve: Stress-testing translations

Extends the testing suite with several fuzzy tests
for binary string tranlations from Albumentations
core image processing library.

https://github.com/albumentations-team/albucore/blob/c0e924b9d2e74f787be413c33b05f42575cdc2c7/tests/test_lut.py#L25-L33

Co-authored-by: Vladimir Iglovikov <[email protected]>

scripts/test.py

@@ -1,6 +1,6 @@
 from random import choice, randint
 from string import ascii_lowercase
-from typing import Optional
+from typing import Optional, Sequence, Dict
 import tempfile
 import os
 
@@ -718,6 +718,63 @@ def test_alignment_score_random(first_length: int, second_length: int):
     ) == -baseline_edit_distance(a, b)
 
 
+def baseline_translate(body: str, lut: Sequence) -> str:
+    return "".join([chr(lut[ord(c)]) for c in body])
+
+
+def translation_table_to_dict(lut: Sequence) -> Dict[str, str]:
+    return {chr(i): chr(lut[i]) for i in range(256)}
+
+
+@pytest.mark.skipif(not numpy_available, reason="NumPy is not installed")
+@pytest.mark.parametrize("length", range(1, 300))
+def test_translations(length: int):
+
+    map_identity = np.arange(256, dtype=np.uint8)
+    map_invert = np.arange(255, -1, -1, dtype=np.uint8)
+    map_threshold = np.where(np.arange(256) > 127, 255, 0).astype(np.uint8)
+    dict_identity = translation_table_to_dict(map_identity)
+    dict_invert = translation_table_to_dict(map_invert)
+    dict_threshold = translation_table_to_dict(map_threshold)
+    view_identity = memoryview(map_identity)
+    view_invert = memoryview(map_invert)
+    view_threshold = memoryview(map_threshold)
+
+    body = get_random_string(length=length)
+    body_bytes = body.encode("utf-8")
+
+    # Check mapping strings and byte-strings into new strings
+    assert sz.translate(body, view_identity) == body
+    assert sz.translate(body_bytes, view_identity) == body_bytes
+    assert sz.translate(body_bytes, view_identity) == body_bytes.translate(
+        view_identity
+    )
+    assert sz.translate(body_bytes, view_invert) == body_bytes.translate(view_invert)
+    assert sz.translate(body_bytes, view_threshold) == body_bytes.translate(
+        view_threshold
+    )
+
+    # Check in-place translations
+    body_after_identity = str(body)
+    sz.translate(body, view_identity, inplace=True)
+    assert body == body_after_identity.translate(dict_identity)
+    body_after_invert = str(body)
+    sz.translate(body, view_invert, inplace=True)
+    assert body == body_after_invert.translate(dict_invert)
+    body_after_threshold = str(body)
+    sz.translate(body, view_threshold, inplace=True)
+    assert body == body_after_threshold.translate(dict_threshold)
+
+
+@pytest.mark.repeat(3)
+@pytest.mark.parametrize("length", range(1, 300))
+@pytest.mark.skipif(not numpy_available, reason="NumPy is not installed")
+def test_translations_random(length: int):
+    body = get_random_string(length=length)
+    lut = np.random.randint(0, 256, size=256, dtype=np.uint8)
+    assert sz.translate(body, memoryview(lut)) == baseline_translate(body, lut)
+
+
 @pytest.mark.parametrize("list_length", [10, 20, 30, 40, 50])
 @pytest.mark.parametrize("part_length", [5, 10])
 @pytest.mark.parametrize("variability", [2, 3])