add support for fits: open, getheader, getval, getdata

tests/test_fits.py

+"""
+Identifier:     tests/test_fits_header_ops.py
+Name:           test_fits_header_ops.py
+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
+"""
+
+import os
+import unittest
+
+from csst_common import fits
+
+test_fits_file = os.path.join(
+    os.environ["UNIT_TEST_DATA_ROOT"],
+    "csst_common/test_fits/hl.fits",
+)
+
+
+class TestFitsHeaderOps(unittest.TestCase):
+
+    def test_fits_open(self):
+        hl = fits.open(test_fits_file)
+        self.assertIsInstance(hl, fits.HDUList)
+
+    def test_fits_header(self):
+        header = fits.getheader(test_fits_file, ext=0)
+        self.assertIsInstance(header, fits.Header)
+
+    def test_fits_getval(self):
+        val = fits.getval(test_fits_file, ext=0, keyword="SIMPLE")
+        self.assertEqual(val, True)
+
+    def test_fits_getdata(self):
+        data = fits.getdata(test_fits_file, ext=0)
+        self.assertEqual(data, None)

tests/test_io.py

@@ -22,7 +22,6 @@ from csst_common.io import (
     generate_meta,
     append_meta,
     extract_meta,
-    fits_open,
 )
 
 
@@ -143,12 +142,3 @@ class TestFitsHeaderOps(unittest.TestCase):
         self.assertIn("META", set(hdulist[0].header.keys()))
         meta = extract_meta(hdulist)
         self.assertEqual(meta["obs_id"], "123456")
-
-    def test_fits_open(self):
-        hl = fits_open(
-            os.path.join(
-                os.environ["UNIT_TEST_DATA_ROOT"],
-                "csst_common/test_fits/hl.fits",
-            )
-        )
-        self.assertTrue(isinstance(hl, fits.HDUList))