Code coverage in e2e tests

Bug Report

Current behavior

Collecting coverage on e2e test results in no files covered.

Input Code

By using

nest new project-name

Then in test/jest-e2e.json add key “collectCoverage”: true

{
  "moduleFileExtensions": ["js", "json", "ts"],
  "rootDir": ".",
  "testEnvironment": "node",
  "testRegex": ".e2e-spec.ts$",
  "transform": {
    "^.+\\.(t|j)s$": "ts-jest"
  },
  "collectCoverage": true
}

Then run

npm run test:e2e

Expected behavior

Code coverage should be shown from app.controller.ts and app.service.ts.

Possible Solution

It seems as the module fixture is not being imported for tracking by jest.

Environment

Nest version: 6.10.1
 
For Tooling issues:
- Node version: v12.10.0
- Platform:  Mac

[velut]

I solved this as follows:

1. Move jest-e2e.json from the test directory to the root directory of the project (where package.json is located)

2. Change the contents of jest-e2e.json to the following:

{
    "moduleFileExtensions": ["js", "json", "ts"],
    "rootDir": ".",
    "testEnvironment": "node",
    "testMatch": ["<rootDir>/test/**/*.e2e-spec.{ts,js}"],
    "transform": {
        "^.+\\.(t|j)s$": "ts-jest"
    },
    "coverageDirectory": "./coverage-e2e"
}

1. Change the test:e2e script inside package.json to:

"test:e2e": "jest --config ./jest-e2e.json"

Now running the test:e2e script with the --coverage flag should generate the required coverage inside the coverage-e2e directory.

[ghost]

This was solved by switching over jest to mocha and using yarn instead of npm.