✅ Add test for model strings

tests/test_models.py

@@ -0,0 +1,21 @@
+import pytest
+import uuid
+
+from creator.studies.models import Study
+from creator.files.models import File, Version, DownloadToken
+from creator.projects.models import Project
+
+
+@pytest.mark.parametrize(
+    "model,expected",
+    [
+        (Study, "SD_00000001"),
+        (File, "SF_00000001"),
+        (Version, "FV_00000001"),
+        (Project, "test/test"),
+    ],
+)
+def test_str(model, expected):
+    """ Test string conversion functions """
+    obj = model(pk=expected)
+    assert str(obj) == expected