Could not find or load xsl resource in WID testing WebSphere ESB component

When testing a mediation component in WebSphere Integration Developer 7 (WID), my xsl transformation failed with this message in the exception trace:

Caused by: com.ibm.wsspi.sibx.mediation.MediationConfigurationException: CWSXM3110E: Exception while initializing the XSL transformation engine with stylesheet 'xslt/MapInput_req_1.xsl'. This has been reported by the following entity: com.ibm.wbiserver.transform.exceptions.TransformServiceConfigurationException: CWSXM3108E: XSLTransform primitive could not find or load the resource 'xslt/MapInput_req_1.xsl'. This has been reported by the following entity: {1}

at com.ibm.ws.sibx.mediation.primitives.util.ExceptionHelper.newMediationConfigurationException(ExceptionHelper.java:96)

at com.ibm.ws.sibx.mediation.primitives.xslt.XSLTMediation.obtainTransformer(XSLTMediation.java:1380)

at com.ibm.ws.sibx.mediation.primitives.xslt.XSLTMediation.init(XSLTMediation.java:574)

at com.ibm.ws.sibx.scax.mediation.component.ESBFlowBuilder.createJavaMediationPrimitive(ESBFlowBuilder.java:1047)

... 54 more

Refer to the server logs for more information.

And in the systemout.log this trace was available:

 

[17/03/11 13:51:57:880 CET] 00000033 MFCImplementa E   CWSXM0202E: An unexpected exception occurred when processing mediation flow for component AuthenticationMediation in module AuthenticationMediation: CWSXM1025E: An unexpected exception occurred when the flow was called: CWSXM0111E:  Service runtime exception calling an import from mediation component AuthenticationMediation in module AuthenticationMediation: CWSXM0206E: An unexpected exception occurred.: com.ibm.ws.sibx.scax.mediation.component.FlowBuildException: CWSXM1007E: Mediation primitive MapToMember in mediation component AuthenticationMediation in module AuthenticationMediation encountered a problem during initialization.

CWSXM3108E: XSLTransform primitive could not find or load the resource 'xslt/MapToMember_res_1.xsl'.

 When opening the project the Enterprise Explorer, I could see that the xsl file was not there for MapToMember_Res_1.map. Normally the xsl file s are generated when building.

Luckily I found a workaround:

I could force WID to generate the xsl file by testing the transformation in the mapping editor of the transformation.

 Hitting the Test Map button (second from the right), made WID generate the xsl file! Sometimes it was not generated. Then I had to really execute the test before the xsl file was generated...

When deploying the module and testing the component, the xsl file was picked up, and the mediation completed successfully. One the problem persisted. The good old remove, restart, re-add of the project gave the final breakthrough.