diff --git a/src/erlcloud_aws.erl b/src/erlcloud_aws.erl
index b5ff9bcf3..0585b049d 100644
--- a/src/erlcloud_aws.erl
+++ b/src/erlcloud_aws.erl
@@ -130,7 +130,7 @@ aws_request4_no_update(Method, Protocol, Host, Port, Path, Params, Service, #aws
 
 
 -spec aws_request_form(Method :: atom(), Protocol :: undefined | string(), Host :: string(),
-                        Port :: undefined | integer() | string(), Path :: string(), Form :: string(),
+                        Port :: undefined | integer() | string(), Path :: string(), Form :: iodata(),
                         Headers :: list(), Config :: aws_config()) -> {ok, binary()} | {error, tuple()}.
 aws_request_form(Method, Protocol, Host, Port, Path, Form, Headers, Config) ->
     UProtocol = case Protocol of
@@ -321,7 +321,7 @@ request_to_return(#aws_request{response_type = error,
 sign_v4(Config, Headers, Payload, Region, Service) ->
     sign_v4(post, Config, Headers, [], Payload, Region, Service).
 
--spec sign_v4(atom(), aws_config(), headers(), binary(), binary(), string(), string()) -> headers().
+-spec sign_v4(atom(), aws_config(), headers(), string(), iodata(), string(), string()) -> headers().
 sign_v4(Method, Config, Headers, QueryParams, Payload, Region, Service) ->
     Date = iso_8601_basic_time(),
     Headers1 = [{"x-amz-date", Date} | Headers],
diff --git a/test/erlcloud_as_tests.erl b/test/erlcloud_as_tests.erl
index dd49e00ba..188daffbe 100644
--- a/test/erlcloud_as_tests.erl
+++ b/test/erlcloud_as_tests.erl
@@ -49,7 +49,7 @@ terminate_tests(_) ->
     
 mocked_aws_xml() ->
     meck:expect(erlcloud_aws, default_config, [{[], #aws_config{}}]),
-    meck:expect(erlcloud_aws, aws_request_xml2, [
+    meck:expect(erlcloud_aws, aws_request_xml4, [
                                                  mocked_groups(), 
                                                  mocked_instances(),
                                                  mocked_launch_configs(),
@@ -63,7 +63,7 @@ mocked_groups() ->
                        {"Action", "DescribeAutoScalingGroups"}, 
                        {"Version", '_'}, 
                        {"MaxRecords", '_'}], 
-      '_'], parsed_mock_response("
+      "autoscaling", '_'], parsed_mock_response("
 <DescribeAutoScalingGroupsResponse xmlns=\"http://autoscaling.amazonaws.com/doc/2011-01-01/\">
 <DescribeAutoScalingGroupsResult>
     <AutoScalingGroups>
@@ -118,7 +118,7 @@ mocked_instances() ->
                        {"Action", "DescribeAutoScalingInstances"}, 
                        {"Version", '_'}, 
                        {"MaxRecords", '_'}], 
-      '_'], {ok, element(1, xmerl_scan:string("
+      "autoscaling", '_'], {ok, element(1, xmerl_scan:string("
 <DescribeAutoScalingInstancesResponse xmlns=\"http://autoscaling.amazonaws.com/doc/2011-01-01/\">
   <DescribeAutoScalingInstancesResult>
     <AutoScalingInstances>
@@ -151,7 +151,7 @@ mocked_launch_configs() ->
                        {"Action", "DescribeLaunchConfigurations"}, 
                        {"Version", '_'}, 
                        {"MaxRecords", '_'}], 
-      '_'], parsed_mock_response("
+      "autoscaling", '_'], parsed_mock_response("
 <DescribeLaunchConfigurationsResponse xmlns=\"http://autoscaling.amazonaws.com/doc/2011-01-01/\">
   <DescribeLaunchConfigurationsResult>
     <LaunchConfigurations>
@@ -195,7 +195,7 @@ mocked_activity() ->
                        {"Version", "2011-01-01"}, 
                        {"InstanceId", "i-bdae7a84"}, 
                        {"ShouldDecrementDesiredCapacity", "true"}],
-      '_'], parsed_mock_response("
+      "autoscaling", '_'], parsed_mock_response("
 <TerminateInstanceInAutoScalingGroupResponse xmlns=\"http://autoscaling.amazonaws.com/doc/2011-01-01/\">
   <TerminateInstanceInAutoScalingGroupResult>
     <Activity>