💚 udpate unit tests

Author: chfw

tests/test_multiple_sheets.py

@@ -60,7 +60,7 @@ def test_load_a_single_sheet2(self):
     def test_load_a_single_sheet3(self):
         pyexcel.get_book(file_name=self.testfile, sheet_index=10000)
 
-    @raises(ValueError)
+    @raises(KeyError)
     def test_load_a_single_sheet4(self):
         pyexcel.get_book(file_name=self.testfile, sheet_name="Not exist")