diff --git a/httprunner/context.py b/httprunner/context.py
index 11d7736d..e4799c8c 100644
--- a/httprunner/context.py
+++ b/httprunner/context.py
@@ -17,6 +17,7 @@ class Context(object):
         self.testset_shared_variables_mapping = OrderedDict()
         self.testcase_variables_mapping = OrderedDict()
         self.testcase_parser = testcase.TestcaseParser()
+        self.evaluated_validators = []
         self.init_context()
 
     def init_context(self, level='testset'):
diff --git a/httprunner/runner.py b/httprunner/runner.py
index ca7b49db..538143f9 100644
--- a/httprunner/runner.py
+++ b/httprunner/runner.py
@@ -156,6 +156,14 @@ class Runner(object):
         except KeyError:
             raise exceptions.ParamsError("URL or METHOD missed!")
 
+        # TODO: move method validation to json schema
+        valid_methods = ["GET", "HEAD", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"]
+        if method.upper() not in valid_methods:
+            err_msg = u"ParamsError: invalid HTTP method! => {}\n".format(method)
+            err_msg += "available HTTP methods: {}".format("/".join(valid_methods))
+            logger.log_error(err_msg)
+            raise exceptions.ParamsError(err_msg)
+
         logger.log_info("{method} {url}".format(method=method, url=url))
         logger.log_debug("request kwargs(raw): {kwargs}".format(kwargs=parsed_request))