diff --git a/java/testFramework/src/com/intellij/codeInsight/daemon/quickFix/LightQuickFixTestCase.java b/java/testFramework/src/com/intellij/codeInsight/daemon/quickFix/LightQuickFixTestCase.java
index 4c25eb27de4f..39221ecff1cf 100644
--- a/java/testFramework/src/com/intellij/codeInsight/daemon/quickFix/LightQuickFixTestCase.java
+++ b/java/testFramework/src/com/intellij/codeInsight/daemon/quickFix/LightQuickFixTestCase.java
@@ -186,7 +186,9 @@ public abstract class LightQuickFixTestCase extends LightDaemonAnalyzerTestCase
     PsiFile file = getFile();
     WriteAction.run(() -> {
       try {
-        // Test that action will automatically clear the read-only attribute if modification is necessary
+        // Test that action will automatically clear the read-only attribute if modification is necessary.
+        // If your test fails due to this, make sure that your quick-fix/intention has the following line:
+        // if (!FileModificationService.getInstance().prepareFileForWrite(file)) return;
         ReadOnlyAttributeUtil.setReadOnlyAttribute(file.getVirtualFile(), true);
       }
       catch (IOException e) {