added verbose to read_test_image

csst_proto/flip_image.py

@@ -32,4 +32,5 @@ def flip_image(img: np.ndarray) -> np.ndarray:
 def read_test_image():
     """ read test image """
     fp_img = PACKAGE_PATH + "/data/test_image.txt"
+    print("reading file {} ...".format(fp_img))
     return np.loadtxt(fp_img, dtype=int)