Added fast tests.

tests/conftest.py

@@ -0,0 +1,17 @@
+#!/usr/bin/python3
+
+import pytest
+
+
+def pytest_addoption(parser):
+    parser.addoption(
+        "--fast", action="store_true", help="Run only fast tests")
+
+
+def pytest_collection_modifyitems(config, items):
+    if config.getoption("--fast"):
+        skip_slow = pytest.mark.skip(reason="Runs only without --fast option.")
+
+        for item in items:
+            if "slow" in item.keywords:
+                item.add_marker(skip_slow)

tests/formats/test_id3.py

@@ -1,15 +1,35 @@
 #!/usr/bin/python3
 
+import pytest
+from io import BytesIO
+
 from smalltag import SmallTag
 
 
-# chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_ "
+def test_written_gets_recognized():
+    # avoid writing to the real file by using a BytesIO
+    tag = SmallTag.get("formats/test.mp3", file_obj=BytesIO(b""))
 
+    tag.title = "A normal title."
+    tag.artist = "An artist."
+    tag.album = "The album."
+    tag.track = 1234
+
+    tag = SmallTag.get("formats/test.mp3", file_obj=BytesIO(tag._compose_id3v2_tag()))
+
+    assert tag.title == "A normal title."
+    assert tag.artist == "An artist."
+    assert tag.album == "The album."
+    assert tag.track == 1234
+
+
+# chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_ "
 # no "b" because there is a bug in TinyTag 2.1.0 that removes "b"s if they are at the beginning of a string
 chars = "acdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 _-"
 
 
-def test_written_gets_recognized():
+@pytest.mark.slow
+def test_full_written_gets_recognized():
     for char1 in chars:
         for char2 in chars:
             field_content = f"{char1}{char2}Test{char2}{char1}"
@@ -27,15 +47,3 @@ def test_written_gets_recognized():
             assert tag.title == field_content
             assert tag.artist == field_content
             assert tag.album == field_content
-
-
-def test_int_converted_to_numerical_string():
-    tag = SmallTag.get("formats/test.mp3")
-
-    tag.track = 123
-
-    tag.write()
-
-    tag = SmallTag.get("formats/test.mp3")
-
-    assert tag.track == 123