diff --git a/pmd-apex/src/test/java/net/sourceforge/pmd/lang/apex/ast/ApexParsingHelper.java b/pmd-apex/src/test/java/net/sourceforge/pmd/lang/apex/ast/ApexParsingHelper.java
index 6b2dfecf23..5fb0ea501d 100644
--- a/pmd-apex/src/test/java/net/sourceforge/pmd/lang/apex/ast/ApexParsingHelper.java
+++ b/pmd-apex/src/test/java/net/sourceforge/pmd/lang/apex/ast/ApexParsingHelper.java
@@ -4,6 +4,8 @@
 
 package net.sourceforge.pmd.lang.apex.ast;
 
+import net.sourceforge.pmd.lang.LanguageVersion;
+import net.sourceforge.pmd.lang.LanguageVersionHandler;
 import net.sourceforge.pmd.lang.apex.ApexLanguageModule;
 import net.sourceforge.pmd.lang.ast.RootNode;
 import net.sourceforge.pmd.lang.ast.test.BaseParsingHelper;
@@ -22,4 +24,9 @@ public class ApexParsingHelper extends BaseParsingHelper<ApexParsingHelper, Root
         return new ApexParsingHelper(params);
     }
 
+    @Override
+    protected void postProcessing(LanguageVersionHandler handler, LanguageVersion lversion, RootNode rootNode) {
+        super.postProcessing(handler, lversion, rootNode);
+        handler.getMultifileFacade().start(rootNode);
+    }
 }
diff --git a/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt b/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
index 1c509ab5e0..6a58f5cd0c 100644
--- a/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
+++ b/pmd-lang-test/src/main/kotlin/net/sourceforge/pmd/lang/ast/test/BaseParsingHelper.kt
@@ -128,7 +128,7 @@ abstract class BaseParsingHelper<Self : BaseParsingHelper<Self, T>, T : RootNode
     /**
      * Called only if [Params.doProcess] is true.
      */
-    protected open fun postProcessing(handler: LanguageVersionHandler, lversion: LanguageVersion, rootNode: T?) {
+    protected open fun postProcessing(handler: LanguageVersionHandler, lversion: LanguageVersion, rootNode: T) {
         val astAnalysisContext = object : AstAnalysisContext {
             override fun getTypeResolutionClassLoader(): ClassLoader = javaClass.classLoader