add support for fits: write test FITS file in setUp

tests/test_fits.py

@@ -5,8 +5,7 @@ Description:    test append_header
 Author:         Bo Zhang
 Created:        2023-12-15
 Modified-History:
-    2023-12-15, Bo Zhang, add TestFitsHeaderOps.test_append_header
-    2023-12-15, Bo Zhang, add TestFitsHeaderOps.test_reformat_header
+    2025-10-23, Bo Zhang, add tests for fits operations
 """
 
 import os