Assessing karma: quantifying the reach of unexamined code

Question

Assessing karma: quantifying the reach of unexamined code

I successfully implemented testing using Karma and Webpack for my Typescript sandbox project. The code coverage data is gathered by Istanbul Instrumenter Loader, but I am facing an issue where the reported coverage of 100% is misleading because it only includes modules imported in the tests.

While looking for a solution, I came across a section in the readme of Istanbul Instrumenter Loader on Github:

To generate a code coverage report for all components (including untested ones), you need to import both all sources and 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 imports everything from index files within the source directory. My main query is: how can I translate this snippet to Typescript without relying on the import * from * workaround? Or is there a more efficient approach?

Edit

I found a related question on importing all files from a folder in Typescript here. Does this imply that I need an index.ts file where I manually import each module whenever a new one is added? There must be a better way.

Edit 2

If anyone knows of tools that can generate coverage reports for the entire codebase while supporting Typescript + Webpack + Karma + Mocha, I would appreciate your suggestions. I tried using nyc but was unable to get any code coverage results.

Edit 3

Here's the translation of the above index.js snippet into Typescript:

declare const require: any;

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

Edit 4

A new karma plugin named karma-sabarivka-reporter has been developed to address the coverage statistics issue. Refer to the accepted answer for more information.

javascript typescript webpack karma-runner

Answer 1

Answer №1

IMPORTANT INFORMATION:

This response does not offer a solution to the problem presented above; it is fundamentally incorrect. Please refer to the comments for further details.

A useful feature available in NYC is the coverage support for untested code, which can be achieved by using the --all flag. Assuming that your test command within the package.json file looks like this:

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

To test coverage after installing nyc and ts-node, you can incorporate the following command into your process. This command assumes that the source code to be checked for coverage is located in the src directory.

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

The --all flag checks all files for coverage.
The --extension .ts option is used to inspect all TypeScript files, but more extensions can be added such as --extension .ts --extension .tsx.
The --include src specifies the directory to check for coverage.
The -- require ts-node/register directive helps NYC interpret TypeScript code.

Following these steps should result in the inclusion of all .ts files in the coverage report.

Please note that utilizing ts-node/register might lead to issues with line numbers on reports. If this occurs, consider implementing source map support as well.

Answer 2

IMPORTANT INFORMATION:

This response does not offer a solution to the problem presented above; it is fundamentally incorrect. Please refer to the comments for further details.

A useful feature available in NYC is the coverage support for untested code, which can be achieved by using the --all flag. Assuming that your test command within the package.json file looks like this:

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

To test coverage after installing nyc and ts-node, you can incorporate the following command into your process. This command assumes that the source code to be checked for coverage is located in the src directory.

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

The --all flag checks all files for coverage.
The --extension .ts option is used to inspect all TypeScript files, but more extensions can be added such as --extension .ts --extension .tsx.
The --include src specifies the directory to check for coverage.
The -- require ts-node/register directive helps NYC interpret TypeScript code.

Following these steps should result in the inclusion of all .ts files in the coverage report.

Please note that utilizing ts-node/register might lead to issues with line numbers on reports. If this occurs, consider implementing source map support as well.

Answer 3

Answer №2

If you're working on projects that are tested using Karma + Istanbul as the coverage reporter, I have developed a karma plugin that includes all project files in the coverage statistic - https://github.com/kopach/karma-sabarivka-reporter.

To utilize this plugin, simply run

npm install --save-dev karma-sabarivka-reporter

Don't forget to update your karma.conf.js file with the following configuration:

reporters: [
  // ...
  'sabarivka'
  // 'coverage-istanbul' or 'coverage' (remember, order matters for the 'coverage' reporter)
  // ...
],
coverageReporter: {
  include: [
      // Specify included patterns first
      'src/**/*.(ts|js)',
      // Then specify "do not touch" patterns (begin each statement with `!`)
      '!src/main.(ts|js)',
      '!src/**/*.spec.(ts|js)',
      '!src/**/*.module.(ts|js)',
      '!src/**/environment*.(ts|js)'
  ]
},

Answer 4

If you're working on projects that are tested using Karma + Istanbul as the coverage reporter, I have developed a karma plugin that includes all project files in the coverage statistic - https://github.com/kopach/karma-sabarivka-reporter.

To utilize this plugin, simply run

npm install --save-dev karma-sabarivka-reporter

Don't forget to update your karma.conf.js file with the following configuration:

reporters: [
  // ...
  'sabarivka'
  // 'coverage-istanbul' or 'coverage' (remember, order matters for the 'coverage' reporter)
  // ...
],
coverageReporter: {
  include: [
      // Specify included patterns first
      'src/**/*.(ts|js)',
      // Then specify "do not touch" patterns (begin each statement with `!`)
      '!src/main.(ts|js)',
      '!src/**/*.spec.(ts|js)',
      '!src/**/*.module.(ts|js)',
      '!src/**/environment*.(ts|js)'
  ]
},

Assessing karma: quantifying the reach of unexamined code

test/index.js

Edit

Edit 2

Edit 3

Edit 4

Answer №1

IMPORTANT INFORMATION:

Answer №2

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