add support for import module custom functions

test/data/demo_import_functions.yml

@@ -0,0 +1,41 @@
+- config:
+    name: "create user testsets."
+    import_module_functions:
+        - test.data.custom_functions
+    variable_binds:
+        - TOKEN: debugtalk
+        - json: {"name": "user", "password": "123456"}
+        - random: {"func": "gen_random_string", "args": [5]}
+        - authorization: {"func": "gen_md5", "args": ["${TOKEN}", "${json}", "${random}"]}
+
+- test:
+    name: create user which does not exist
+    variable_binds:
+        - json: {"name": "user", "password": "123456"}
+    request:
+        url: http://127.0.0.1:5000/api/users/1000
+        method: POST
+        headers:
+            Content-Type: application/json
+            authorization: "${authorization}"
+            random: "${random}"
+        json: "${json}"
+    validators:
+        - {"check": "status_code", "comparator": "eq", "expected": 201}
+        - {"check": "content.success", "comparator": "eq", "expected": true}
+
+- test:
+    name: create user which does not exist
+    variable_binds:
+        - json: {"name": "user", "password": "123456"}
+    request:
+        url: http://127.0.0.1:5000/api/users/1000
+        method: POST
+        headers:
+            Content-Type: application/json
+            authorization: "${authorization}"
+            random: "${random}"
+        json: "${json}"
+    validators:
+        - {"check": "status_code", "comparator": "eq", "expected": 500}
+        - {"check": "content.success", "comparator": "eq", "expected": false}