Core: Check MPU threshold

tosfs/tests/test_tosfs.py

@@ -753,7 +753,7 @@ def test_file_write_mpu_threshold_check(
     file_name = random_str()
     content = "a" * 1 * 1024
     block_size = 4 * 1024
-    with pytest.raises(ValueError, match="Block size must be >= 4MB.") and tosfs.open(
+    with pytest.raises(ValueError, match="Block size must be >= 4MB."), tosfs.open(
         f"{bucket}/{temporary_workspace}/{file_name}", "w", block_size=block_size
     ) as f:
         f.write(content)