diff --git a/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts b/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts
index 10c4f62d1bcf..4817935c52f7 100644
--- a/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts
+++ b/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts
@@ -481,6 +481,7 @@ describe('themeConfig', () => {
     const prismConfig = {
       prism: {
         additionalLanguages: ['kotlin', 'java'],
+        theme: darkTheme,
       },
     };
     expect(testValidateThemeConfig(prismConfig)).toEqual({