Improve error message for a REST test (#53037)

src/rest/tests/openapi-schema.js

@@ -121,7 +121,10 @@ describe('markdown for each rest version', () => {
           Object.keys(openApiSchema[version][category]),
           `The REST version: ${version}'s category: ${category} does not include the subcategory: ${subCategory}. Please check file: ${file}`,
         ).toContain(subCategory)
-        expect(categoryApplicableVersions[category]).toContain(version)
+        expect(
+          categoryApplicableVersions[category],
+          `The versions that apply to category ${category} does not contain the ${version}, as is expected. Please check the versions for file ${file} or look at the index that governs that file (in its parent directory).`,
+        ).toContain(version)
       }
     })
   })