rename and api defined

tests/test_common_db.py

 import unittest
 
-from csst.dfs.api.local.common.db import DBClient
+from csst_dfs_api_local.common.db import DBClient
 
 class DBClientTestCase(unittest.TestCase):
     def setUp(self):

tests/test_ifs_fits.py

+import unittest
+
+from csst_dfs_api_local.ifs import FitsApi
+
+class IFSFitsTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.api = FitsApi()
+
+    def test_find(self):
+        files = self.api.find()
+        print("find ", files)
+    
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