Cursor testing

Cursor-Generated Unit Tests Failing Immediately

You asked Cursor to generate unit tests for your code, but the tests fail immediately when you run them. The failures range from import/module resolution errors and incorrect assertions to tests that reference functions or methods that don't exist in your codebase. The tests look plausible but don't actually test your real implementation.

AI-generated tests are one of the most requested features, but they're also one of the most error-prone. Cursor generates tests based on its understanding of your code, but may hallucinate function signatures, assume different export patterns, or use the wrong testing framework syntax. The tests compile but don't accurately reflect your actual code.

Running these failing tests wastes time debugging test code instead of production code, and if you force them to pass by adjusting the tests, you end up with tests that don't actually verify correct behavior.

Error Messages You Might See

Cannot find module '../utils/helpers' from 'tests/helpers.test.ts' TypeError: functionName is not a function Expected: 200, Received: undefined ReferenceError: describe is not defined Error: No test suite found in file TS2305: Module '"../src/service"' has no exported member 'processData'
Cannot find module '../utils/helpers' from 'tests/helpers.test.ts'TypeError: functionName is not a functionExpected: 200, Received: undefinedReferenceError: describe is not definedError: No test suite found in fileTS2305: Module '"../src/service"' has no exported member 'processData'

Common Causes

  • Wrong import paths — Cursor generates imports like import { func } from '../utils' when the actual path is import { func } from '../lib/utils'
  • Hallucinated function signatures — Tests call functions with parameters that don't match the actual implementation (wrong parameter count, types, or names)
  • Wrong testing framework syntax — Cursor generated Jest syntax but the project uses Vitest, or generated Mocha syntax for a Jest project
  • Missing test configuration — Jest/Vitest config doesn't have the necessary transformers, module mappers, or setup files for the generated tests to run
  • Incorrect assertion values — Tests assert expected values that don't match what the function actually returns, based on the AI's assumption of behavior
  • Private or unexported functions tested directly — Tests try to import and test internal functions that aren't exported from the module

How to Fix It

  1. Verify import paths match your project structure — Check every import statement in the generated tests against your actual file tree. Fix paths to match the real module locations
  2. Cross-reference function signatures — Open the source file being tested alongside the test file. Verify that every function call in the test matches the actual parameters, return types, and export names
  3. Check your test framework configuration — Verify your jest.config.js or vitest.config.ts matches what the tests expect. Ensure TypeScript, JSX, and module alias transformations are configured
  4. Run tests one at a time — Use jest --testPathPattern=filename or vitest run filename to run one test file at a time and fix issues incrementally
  5. Treat generated tests as scaffolding — Don't expect AI tests to be correct out of the box. Use them as a starting structure and manually verify/fix each assertion against the actual code behavior
  6. Add your testing patterns to .cursorrules — Specify your test framework, file naming conventions, and import patterns so Cursor generates compatible tests

Real developers can help you.

Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. Tejas Chokhawala Tejas Chokhawala Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript. Focused on performance, clean architecture and shipping fast. Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools. Jared Hasson Jared Hasson Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever rayush33 rayush33 JavaScript (React.js, React Native, Node.js) Developer with demonstrated industry experience of 4+ years, actively looking for opportunities to hone my skills as well as help small-scale business owners with solutions to technical problems legrab legrab I'll fill this later Milan Surelia Milan Surelia Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems. Expertise: 💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web. 🖋️ Sharing insights through technical writing, blogging, and open-source contributions. 🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences. Notable Achievements: 🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX. 🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development. 🌟 Open source contributions on Github & StackOverflow for Flutter & Dart 🎖️ Worked on improving app performance and user experience with smart solutions. Milan is always happy to connect, work on new ideas, and explore the latest in technology. Bastien Labelle Bastien Labelle Full stack dev w/ 20+ years of experience Caio Rodrigues Caio Rodrigues I'm a full-stack developer focused on building practical and scalable web applications. My main experience is with **React, TypeScript, and modern frontend architectures**, where I prioritize clean code, component reusability, and maintainable project structures. I have strong experience working with **dynamic forms, state management (Redux / React Hook Form), and complex data-driven interfaces**. I enjoy solving real-world problems by turning ideas into reliable software that companies can actually use in their daily operations. Beyond coding, I care about **software quality and architecture**, following best practices for componentization, code organization, and performance optimization. I'm also comfortable working across the stack when needed, integrating APIs, handling business logic, and helping transform prototypes into production-ready systems. My goal is always to deliver solutions that are **simple, efficient, and genuinely useful for the people using them.** zipking zipking I am a technologist and product builder dedicated to creating high-impact solutions at the intersection of AI and specialized markets. Currently, I am focused on PropScan (EstateGuard), an AI-driven SaaS platform tailored for the Japanese real estate industry, and exploring the potential of Archify. As an INFJ-T, I approach development with a "systems-thinking" mindset—balancing technical precision with a deep understanding of user needs. I particularly enjoy the challenge of architecting Vertical AI SaaS and optimizing Small Language Models (SLMs) to solve specific, real-world business problems. Whether I'm in a CTO-level leadership role or hands-on with the code, I thrive on building tools that turn complex data into actionable value. Jacek Rozanski Jacek Rozanski Senior PHP/Symfony developer and DevOps engineer with 20+ years of professional experience, running opcode.pl (web development agency, est. 2004). Day job: I'm the sole backend developer at merketing company where I own and maintain 11 PHP/Symfony microservices on AWS (ECS Fargate, RDS, S3, CloudFront), handle the full CI/CD pipeline (Bitbucket Pipelines, Docker), and manage monitoring with Sentry and CloudWatch. These services handle high request volumes in production every month. What I bring to AI-built apps: - I audit and fix security issues (OWASP methodology), performance bottlenecks, and architectural problems in codebases generated by Cursor, Claude Code, Lovable, Bolt, and v0 - I refactor AI-generated prototypes into production-grade applications with proper error handling, testing, and clean architecture (SOLID, DDD, hexagonal architecture) - I set up the infrastructure AI tools don't touch: AWS hosting, CI/CD pipelines, automated deployments, database optimization, monitoring, and alerting - I integrate external services: payment providers, email systems, partner APIs, SSO/auth Tech stack: PHP 8.x, Symfony, React, Next.js, PostgreSQL, MySQL, Docker, AWS (ECS, RDS, S3, SQS/SNS, CloudFront), Terraform, Supabase. I also use AI tools daily (Claude Code, Cursor) in my own workflow, so I understand both the strengths and the gaps in AI-generated code. Based in Poland (CET timezone). Available for async work and calls during EU/US business hours.

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Frequently Asked Questions

Should I trust AI-generated test assertions?

No. Always verify assertions manually. AI tests often assert what the code 'should' do based on function names, not what it actually does. Run the function manually and compare the output to the test's expected value.

How do I get Cursor to generate better tests?

Provide context by opening the source file in a Cursor tab, specify your test framework in the prompt ('write Jest tests with TypeScript'), and include an example test file from your project so Cursor matches the style.

Related Cursor Issues

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