KieServices ks = KieServices.Factory.get();
KieFileSystem kfs = ks.newKieFileSystem()
.write( "src/main/resources/r1.drl", drl1 );
KieBuilder kieBuilder = ks.newKieBuilder( kfs ).buildAll();
assertEquals( 0, kieBuilder.getResults().getMessages( org.kie.api.builder.Message.Level.ERROR ).size() );
//Add file with error - expect 1 "added" error message
kfs.write( "src/main/resources/r2.drl", drl2_1 );
IncrementalResults addResults = ( (InternalKieBuilder) kieBuilder ).createFileSet( "src/main/resources/r2.drl" ).build();