Add test for all arg differences for singleton locks

src/filelock/_api.py

@@ -143,7 +143,7 @@ def __init__(  # noqa: PLR0913
                 raise RuntimeError(msg)
 
             params_to_check = {
-                "is_thread_local": (thread_local, self.is_thread_local()),
+                "thread_local": (thread_local, self.is_thread_local()),
                 "timeout": (timeout, self.timeout),
                 "mode": (mode, self.mode),
                 "blocking": (blocking, self.blocking),

tests/test_filelock.py

@@ -744,12 +744,19 @@ def test_singleton_locks_are_distinct_per_lock_file(lock_type: type[BaseFileLock
 @pytest.mark.parametrize("lock_type", [FileLock, SoftFileLock])
 def test_singleton_locks_must_be_initialized_with_the_same_args(lock_type: type[BaseFileLock], tmp_path: Path) -> None:
     lock_path = tmp_path / "a"
-    lock = lock_type(str(lock_path), is_singleton=True)  # noqa: F841
-
-    with pytest.raises(ValueError, match="Singleton lock instances cannot be initialized with differing arguments"):
-        lock_type(str(lock_path), timeout=10, is_singleton=True)
-    with pytest.raises(ValueError, match="Singleton lock instances cannot be initialized with differing arguments"):
-        lock_type(str(lock_path), mode=0, is_singleton=True)
+    args: dict[str, Any] = {"timeout": -1, "mode": 0o644, "thread_local": True, "blocking": True}
+    alternate_args: dict[str, Any] = {"timeout": 10, "mode": 0, "thread_local": False, "blocking": False}
+
+    lock = lock_type(str(lock_path), is_singleton=True, **args)
+
+    for arg_name in args:
+        general_msg = "Singleton lock instances cannot be initialized with differing arguments"
+        altered_args = args.copy()
+        altered_args[arg_name] = alternate_args[arg_name]
+        with pytest.raises(ValueError, match=general_msg) as exc_info:
+            lock_type(str(lock_path), is_singleton=True, **altered_args)
+        exc_info.match(arg_name)  # ensure specific non-matching argument is included in exception text
+    del lock
 
 
 @pytest.mark.skipif(hasattr(sys, "pypy_version_info"), reason="del() does not trigger GC in PyPy")