Jest passing tests but --covering option not picking up files - node.js

Question

Problem description:
I have written two tests for a typescript class. Those two tests pass so jest successfully retrieves the test files. I then use the --coverage option but it appears jest is not picking the covered files here.
Here is the output I am getting:
api_jester | PASS src/tests/repositories/user.test.ts
api_jester | User Repository
api_jester | ✓ it should return an empty array (18ms)
api_jester | ✓ should successfully create a user and return its data (7ms)
api_jester |
api_jester | ----------|----------|----------|----------|----------|-------------------|
api_jester | File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
api_jester | ----------|----------|----------|----------|----------|-------------------|
api_jester | All files | 0 | 0 | 0 | 0 | |
api_jester | ----------|----------|----------|----------|----------|-------------------|
api_jester | Test Suites: 1 passed, 1 total
api_jester | Tests: 2 passed, 2 total
api_jester | Snapshots: 0 total
api_jester | Time: 3.208s
api_jester | Ran all test suites.
I have tried playing with the collectCoverageFrom option but without any success. I have tested covering with some simple examples found on github and those were working so the problem is not from my environment. I am guessing I somehow missed something in my configuration but I have spend so much time on this I am getting kind of frustrated so maybe some fresh looks could help..
Project architecture :
config
|__ jest.config.js
|__ tsconfig.json
src
|__tests
| |__repositories
| |__user.test.ts
|__repositories
|___ userRepository
|__User.ts
Jest.config.js :
module.exports = {
preset: "ts-jest",
testEnvironment: "node",
roots: ["../src/tests/"],
transform: {
"^.+\\.tsx?$": "ts-jest"
},
collectCoverageFrom: ["../src/"],
moduleFileExtensions: ["ts", "js", "json"],
coverageDirectory: "../coverage"
};
package.json
{
"name": "theralog_api",
"version": "1.0.0",
"description": "",
"main": "server.js",
"scripts": {
"build": "tsc",
"prettier": "npx prettier --write src/**/*.ts --config ./config/.prettierrc",
"eslint": "npx eslint --config ./config/.eslintrc ./src/**/**/*",
"start:dev": "npx nodemon -L --config ./config/api.nodemon.json",
"test:watch": "npx nodemon -L --config ./config/jester.nodemon.json",
"test:coverage": "npx jest --config ./config/jest.config.js --coverage --colors --watch"
},
"keywords": [],
"author": "",
"license": "ISC",
"devDependencies": {
"#types/compression": "^1.0.1",
"#types/express": "^4.17.1",
"#types/graphql-depth-limit": "^1.1.2",
"#types/jest": "^24.0.23",
"#types/node": "^12.7.12",
"#typescript-eslint/eslint-plugin": "^2.5.0",
"#typescript-eslint/parser": "^2.5.0",
"apollo-server-testing": "2.9.7",
"babel-jest": "^24.9.0",
"eslint": "^6.5.1",
"eslint-config-prettier": "^6.4.0",
"graphql-depth-limit": "^1.1.0",
"graphql-import": "^0.7.1",
"graphql-import-node": "0.0.4",
"jest": "^24.9.0",
"nodemon": "^1.19.3",
"prettier": "^1.18.2",
"ts-jest": "^24.1.0",
"ts-node": "^8.4.1",
"tsconfig-paths": "^3.9.0",
"typescript": "^3.7.2"
},
"dependencies": {
"apollo-server-express": "^2.9.6",
"compression": "^1.7.4",
"cors": "^2.8.5",
"dotenv": "^8.2.0",
"express": "^4.17.1",
"graphql": "^14.5.8",
"http": "0.0.0",
"lodash": "^4.17.15",
"ncp": "^2.0.0",
"pg": "^7.12.1",
"winston": "3.2.1"
}
}
jester.nodemon.json
{
"watch": ["../src"],
"ext": "ts",
"exec": "npx jest --config ./config/jest.config.js --watchAll"
}

Answer 1

You are missing a setting in the jest.config.js, collectCoverage: true
module.exports = {
preset: "ts-jest",
testEnvironment: "node",
roots: ["../src/tests/"],
transform: {
"^.+\\.tsx?$": "ts-jest"
},
collectCoverage: true,
collectCoverageFrom: ["../src/"],
moduleFileExtensions: ["ts", "js", "json"],
coverageDirectory: "../coverage"
};
I also use a more descriptive collectCoverageFrom:
collectCoverageFrom: [
'<rootDir>/src/**/*.ts',
'!<rootDir>/src/**/*.interface.ts',
'!<rootDir>/src/**/*.mock.ts',
'!<rootDir>/src/**/*.module.ts',
'!<rootDir>/src/**/*.spec.ts',
'!<rootDir>/src/**/*.test.ts',
'!<rootDir>/src/**/*.d.ts'
],
This way I exclude a number of files I do not want to count coverage from, such as my modules, mocks, and tests.
My full file with the original Jest init process and the comments from that.
For a detailed explanation regarding each configuration property, visit: the Jest documentation
module.exports = {
// All imported modules in your tests should be mocked automatically
// automock: false,
// Stop running tests after the first failure
// bail: false,
// Respect "browser" field in package.json when resolving modules
// browser: false,
// The directory where Jest should store its cached dependency information
// cacheDirectory: "C:\\Users\\sscott\\AppData\\Local\\Temp\\jest",
// Automatically clear mock calls and instances between every test
// clearMocks: false,
// Indicates whether the coverage information should be collected while executing the test
collectCoverage: true,
// An array of glob patterns indicating a set of files for which coverage information should be collected
collectCoverageFrom: [
'<rootDir>/src/**/*.ts',
'!<rootDir>/src/**/*.mock.ts',
'!<rootDir>/src/**/*.module.ts',
'!<rootDir>/src/**/*.spec.ts',
'!<rootDir>/src/**/*.test.ts',
'!<rootDir>/src/**/*.d.ts'
],
// The directory where Jest should output its coverage files
coverageDirectory: "<rootDir>/docs",
// An array of regexp pattern strings used to skip coverage collection
coveragePathIgnorePatterns: [
"\\\\node_modules\\\\"
],
// A list of reporter names that Jest uses when writing coverage reports
coverageReporters: [
"lcov",
"clover",
"text-summary"
],
// An object that configures minimum threshold enforcement for coverage results
// coverageThreshold: null,
// Make calling deprecated APIs throw helpful error messages
errorOnDeprecated: true,
// Force coverage collection from ignored files usin a array of glob patterns
// forceCoverageMatch: [],
// A path to a module which exports an async function that is triggered once before all test suites
// globalSetup: null,
// A path to a module which exports an async function that is triggered once after all test suites
// globalTeardown: null,
// A set of global variables that need to be available in all test environments
globals: {
"ts-jest": {
"diagnostics": false,
"tsConfig": "tsconfig.json"
}
},
// An array of directory names to be searched recursively up from the requiring module's location
// moduleDirectories: [
// "node_modules"
// ],
// An array of file extensions your modules use
moduleFileExtensions: [
"ts",
"tsx",
"js"
],
// A map from regular expressions to module names that allow to stub out resources with a single module
// moduleNameMapper: {},
// An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
// modulePathIgnorePatterns: [],
// Activates notifications for test results
// notify: false,
// An enum that specifies notification mode. Requires { notify: true }
// notifyMode: "always",
// A preset that is used as a base for Jest's configuration
// preset: null,
// Run tests from one or more projects
// projects: null,
// Use this configuration option to add custom reporters to Jest
// reporters: undefined,
// Automatically reset mock state between every test
// resetMocks: false,
// Reset the module registry before running each individual test
// resetModules: false,
// A path to a custom resolver
// resolver: null,
// Automatically restore mock state between every test
// restoreMocks: false,
// The root directory that Jest should scan for tests and modules within
// rootDir: null,
// A list of paths to directories that Jest should use to search for files in
roots: [
"<rootDir>/src"
],
// Allows you to use a custom runner instead of Jest's default test runner
// runner: "jest-runner",
// The paths to modules that run some code to configure or set up the testing environment before each test
// setupFiles: [],
// The path to a module that runs some code to configure or set up the testing framework before each test
// setupTestFrameworkScriptFile: null,
// A list of paths to snapshot serializer modules Jest should use for snapshot testing
// snapshotSerializers: [],
// The test environment that will be used for testing
testEnvironment: "node",
// Options that will be passed to the testEnvironment
// testEnvironmentOptions: {},
// Adds a location field to test results
// testLocationInResults: false,
// The glob patterns Jest uses to detect test files
testMatch: [
"**/*.spec.ts"
],
// An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
// testPathIgnorePatterns: [
// "\\\\node_modules\\\\"
// ],
// The regexp pattern Jest uses to detect test files
// testRegex: "",
// This option allows the use of a custom results processor
// testResultsProcessor: null,
// "testResultsProcessor": "jest-jenkins-reporter",
// This option allows use of a custom test runner
// testRunner: "jasmine2",
// This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
// testURL: "http://localhost",
// Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
// timers: "real",
// A map from regular expressions to paths to transformers
transform: {
"^.+\\.(ts|tsx)$": "ts-jest"
},
// An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
// transformIgnorePatterns: [
// "\\\\node_modules\\\\"
// ],
// An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
// unmockedModulePathPatterns: undefined,
// Indicates whether each individual test should be reported during the run
verbose: false
// An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
// watchPathIgnorePatterns: [],
// Whether to use watchman for file crawling
// watchman: true,
};

Answer 2

After a lot of research at several pages, this worked for me to get the coverage report:
put below line under scripts:
"test:coverage": "set CI=true && react-scripts test --coverage",
And, add below code for jest configuration in package.json file as below:
"jest": {
"collectCoverageFrom": [
"**/*.{js,jsx}",
"!**/node_modules/**",
"!**/coverage/**",
"!**/serviceWorker.js",
"!**/index.js"
],
"coveragePathIgnorePatterns": [
"/node_modules/",
"package.json",
"package-lock.json"
]
}
And, then run
npm run test:coverage

Answer 3

Apparently you have to add your source files to roots to make it work. See this PR comment.
Instead of this:
roots: ["../src/tests/"]
Also include your source files:
roots: ["../src/tests/", "../src/repositories/"]
After that and having the correct collectCoverageFrom, all files with 0% coverage were detected as expected.