add test code for testing config saver

test/saver/test_config_saver.py

@@ -0,0 +1,21 @@
+import os
+
+import unittest
+
+from fastNLP.loader.config_loader import ConfigSection, ConfigLoader
+from fastNLP.saver.config_saver import ConfigSaver
+
+
+class TestConfigSaver(unittest.TestCase):
+    def test_case_1(self):
+        config_saver = ConfigSaver("./test/loader/config")
+        #config_saver = ConfigSaver("./../loader/config")
+
+        section = ConfigSection()
+        section["test"] = 105
+        section["tt"] = 0.5
+        section["str"] = "this is a str"
+        config_saver.save_config_file("test", section)
+        config_saver.save_config_file("another-test", section)
+        config_saver.save_config_file("one-another-test", section)
+