Forgot to add the files related to the work done for guidelines for package tests organisation (http://developer.symbian.org/wiki/index.php/Guidelines_for_Package_Test_Organisation).
<?xml version="1.0"?>
<!DOCTYPE SystemDefinition [
<!ENTITY layer_real_source_path "sf/app/musicplayer" >
]>
<SystemDefinition name="avdomain" schema="1.4.0">
<systemModel>
<!-- Common file for prebuild layers-->
<layer name="app_layer">
<module name="musicplayer">
<unit unitID="musicplayer" mrp="" bldFile="&layer_real_source_path;/group" name="musicplayer" />
</module>
</layer>
<layer name="api_test_layer">
<module name="musicplayer_tsrc">
<unit unitID="musicplayer_tsrc" name="musicplayer_tsrc" bldFile="&layer_real_source_path;/tsrc/group" mrp="" />
</module>
</layer>
<layer name="app_musicplayer_layer">
<module name="musicplayer_group">
<unit unitID="musicplayer_group" mrp="" bldFile="&layer_real_source_path;/group" name="musicplayer_group" />
</module>
</layer>
</systemModel>
</SystemDefinition>