Karma tests: measure coverage for untested code

Question

I have successfully set up testing with Karma and Webpack for my sandbox project written in Typescript . The code coverage metrics are collected by Istanbul Instrumenter Loader. What bothers me is that I get the coverage reported only for the modules that are being imported in the tests , so the reported coverage of 100% is in fact a dirty lie.

Looking for a solution, I have found a passage in Istanbul Instrumenter Loader's readme :

To create a code coverage report for all components (even for those for which you have no tests yet) you have to require all the 1) sources and 2) tests.

test/index.js

 // requires all tests in `project/test/src/components/**/index.js` const tests = require.context('./src/components/', true, /index\\.js$/); tests.keys().forEach(tests); // requires all components in `project/src/components/**/index.js` const components = require.context('../src/components/', true, /index\\.js$/); components.keys().forEach(components);

If I understand correctly, this snippet walks over all index files in source dir and imports everything from them. My question is: how to correctly translate this snippet to Typescript? Or is there a better solution that does not require the import * from * workaround?

Edit

I've found this question: Typescript 1.8 modules: import all files from folder . Does this mean that I need an index.ts file where I have to import each module? This would mean that each time I introduce a new module file, I have to manually add its import to index.ts ? There must be a better way.

Edit 2

I'm also open to other tools that can generate coverage report for the whole code base, the only condition them being able to cope with the Typescript + Webpack + Karma + Mocha stack. I have tried nyc , but couldn't manage to get any code coverage at all.

Edit 3

Here's the index.js from above translated to Typescript:

declare const require: any;

const ctx = require.context('../src', true, /\.ts$/);
ctx.keys().map(ctx);

Edit 4

There's a karma plugin now called karma-sabarivka-reporter that corrects the coverage statistics. Check out the accepted answer for details.

Answer 1

IMPORTANT:

This answer will not solve the above problem, it's fundamentally wrong. See comments.

---

NYC supports coverage for untested code with --all flag. Assuming your test command in package.json is

"test": "karma start karma.conf.js",

You can test coverage after npm install -D nyc ts-node , you can add the following command and run it. This command expects the source code to check for coverage to be in src directory.

"coverage": "nyc --all --include src --extension .ts --require ts-node/register npm test",

• --all flag is used to check all files for coverage.
• --extension .ts is for checking all TypeScript files, you can add more extension like --extension .ts --extension .tsx .
• --include src is for the directory to check for coverage.
• -- require ts-node/register is to teach NYC to understand TypeScript.

After that you should see all .ts files being included.

Note: Using ts-node/register may cause issues with line numbers on reports. To solve this you will probably need to register source map support as well..

Answer 2

For projects tested using Karma + Istanbul as coverage reporter – I've just created karma plugin, which adds all the files in the project to coverage statistic - https://github.com/kopach/karma-sabarivka-reporter .

To use it -> install npm install --save-dev karma-sabarivka-reporter

And update karma.conf.js like this:

reporters: [
  // ...
  'sabarivka'
  // 'coverage-istanbul' or 'coverage' (reporters order is important for 'coverage' reporter)
  // ...
],
coverageReporter: {
  include: [
      // Specify include pattern(s) first
      'src/**/*.(ts|js)',
      // Then specify "do not touch" patterns (note `!` sign on the beginning of each statement)
      '!src/main.(ts|js)',
      '!src/**/*.spec.(ts|js)',
      '!src/**/*.module.(ts|js)',
      '!src/**/environment*.(ts|js)'
  ]
},