<!--
title: Test dependency management
domain: app-frameworks
topic: Testing
language: Json
source: nestjs/nest
updated: 2020-11-22
url: https://awesomereviewers.com/reviewers/nest-test-dependency-management/
-->

Testing tools and libraries should be placed in `devDependencies` rather than regular dependencies in package.json. Regularly review testing dependencies to identify and remove outdated or redundant packages. For example, if a newer testing tool now includes functionality previously provided by a separate package (like 'nyc' now depending on 'istanbul-lib-coverage' instead of 'istanbul'), remove the redundant dependency.

```json
// Good practice:
"devDependencies": {
  "nunjucks": "^3.2.1",  // For integration tests
  "nyc": "^15.0.0"       // Uses istanbul-lib-coverage internally
}

// Avoid:
"dependencies": {
  "nunjucks": "^3.2.1"   // Wrong place for testing tools
},
"devDependencies": {
  "istanbul": "^0.4.5",  // Redundant with nyc
}
```