How I Added Unit Tests to a Next.js Project Using Vitest (and Why It Matters for Portfolio Projects)

I recently built a SQL and Python interview prep app using Next.js, TypeScript, Supabase, and Vercel, with ChatGPT for code assist. The core of the app is a custom SQL answer checker — a function that evaluates whether a user's SQL query contains the right keywords, avoids forbidden patterns, and selects the right columns. The SQL warmup-questions.ts file contains the promptText and expectedIncludes for each question: export type WarmupQuestion = { slug: string; title: string; promptText: string; expectedIncludes: string[]; }; export const SQL_WARMUP_QUESTIONS: WarmupQuestion[] = [ { slug: "basic-select", title: "Basic SELECT", promptText: "Write a SQL query that returns the name and age columns from the users table.", expectedIncludes: ["select", "name", "age", "from users"], }, { slug: "where-filter", title: "WHERE Filter", promptText: "Write a SQL query that returns all users whose age is greater than or equal to 18.", expectedIncludes: ["select", "from users", "where", "age", ">