I was running the MDLQA-1419 test on qa.moodle.net and I got this feedback (it works but note the notice at the top):

Service Url:
http://qa.moodle.net/mod/lti/service.php

------------ POST RETURNS ------------
<br />
<b>Notice</b>: Undefined index: Content-type in <b>/html/mod/lti/OAuthBody.php</b> on line <b>86</b>
<br />
<?xml version="1.0" encoding="UTF-8"?>
<imsx_POXEnvelopeResponse xmlns="http://www.imsglobal.org/lis/oms1p0/pox">
<imsx_POXHeader>
<imsx_POXResponseHeaderInfo>
<imsx_version>V1.0</imsx_version>
<imsx_messageIdentifier>95279161</imsx_messageIdentifier>
<imsx_statusInfo>
<imsx_codeMajor>success</imsx_codeMajor>
<imsx_severity>status</imsx_severity>
<imsx_description>Grade replace response</imsx_description>
<imsx_messageRefIdentifier>4ecb53495e8a0</imsx_messageRefIdentifier>
</imsx_statusInfo>
</imsx_POXResponseHeaderInfo>
</imsx_POXHeader>
<imsx_POXBody>
<replaceResultResponse/>
</imsx_POXBody>
</imsx_POXEnvelopeResponse>

------------ WE SENT ------------
<?xml version = "1.0" encoding = "UTF-8"?>
<imsx_POXEnvelopeRequest xmlns = "http://www.imsglobal.org/lis/oms1p0/pox">
<imsx_POXHeader>
<imsx_POXRequestHeaderInfo>
<imsx_version>V1.0</imsx_version>
<imsx_messageIdentifier>4ecb53495e8a0</imsx_messageIdentifier>
</imsx_POXRequestHeaderInfo>
</imsx_POXHeader>
<imsx_POXBody>
<replaceResultRequest>
<resultRecord>
<sourcedGUID>
<sourcedId>{"data":

,"hash":"fd4233b731b878e1c30e7e40df47372e68a31198703257b2577d9972d2a0c6a5"}</sourcedId>
</sourcedGUID>
<result>
<resultScore>
<language>en-us</language>
<textString>0.4</textString>
</resultScore>
</result>
</resultRecord>
</replaceResultRequest>
</imsx_POXBody>
</imsx_POXEnvelopeRequest>