Code coverage reports

A code coverage report is a good way to understand the amount and trends of unit test coverage for your Angular project.

To generate the report for your app, execute the following command from your project folder:

$ npx ng test --watch=false --code-coverage

The resulting report will be created as an HTML file under a folder named coverage; execute the following command to view it in your browser:

$ npx http-server -c-1 -o -p 9875 ./coverage

You may need to specify --project for the ng test command. Similarly, the coverage report may be generated in a sub-folder under coverage. You can select the folder to view it.

Here’s the folder-level sample coverage report generated by istanbul for LemonMart:

Figure 10.20: Istanbul code coverage report for LemonMart

You can drill down on a particular folder, such as src/app/auth, and get a file-level report, as shown here:

Figure 10.21: Istanbul code coverage...