diff --git a/packages/ckeditor5-dev-build-tools/tests/config/config.test.ts b/packages/ckeditor5-dev-build-tools/tests/config/config.test.ts
index 9f54d89d8..c560c5d76 100644
--- a/packages/ckeditor5-dev-build-tools/tests/config/config.test.ts
+++ b/packages/ckeditor5-dev-build-tools/tests/config/config.test.ts
@@ -53,7 +53,7 @@ test( '--tsconfig', async () => {
 
 	expect( fileExists.plugins.some( plugin => plugin?.name === 'typescript' ) ).toBe( true );
 	expect( fileDoesntExist.plugins.some( plugin => plugin?.name === 'typescript' ) ).toBe( false );
-	expect( declarationsFalse.plugins.some( plugin => plugin?.name === 'typescript' ) ).toBe( false );
+	expect( declarationsFalse.plugins.some( plugin => plugin?.name === 'typescript' ) ).toBe( true );
 } );
 
 test( '--external', async () => {