docs: add FAQ on generating local test coverage report

PR-URL: #6536
Reviewed-by: Athan Reines <[email protected]>

Author: anandkaranubc

docs/contributing/FAQ.md

@@ -31,6 +31,7 @@ limitations under the License.
 -   [What should I do if JavaScript linting on my commits fails because my function exceeds the maximum permissible number of parameters?](#max-params)
 -   [I have opened a pull request, where can I seek feedback?](#pr-feedback)
 -   [I need to generate fixtures for my tests. How can I do that, and what are the best references for inspiration?](#generate-fixtures)
+-   [How can I generate the test coverage report for a specific package locally?](#test-cov)
 -   [I am facing a `Uninitialized variable` linting error in my C files, how can I fix it?](#uninitialized-variable)
 -   [I have the required packages in the expected paths, but I am still encountering an error like this while compiling the native add-on.](#compilation-error)
 -   [When should I use decimals in examples, benchmarks, and documentation, and when should I avoid them?](#decimal-usage)
@@ -144,6 +145,19 @@ Consider joining our [Gitter channel][stdlib-gitter]! We are proud to have a ver
 
 Tests are a crucial part of any standard library package. We take our goal of achieving 100% test coverage very seriously and expect your work to be backed by tests. Often, you may need to generate fixtures to validate your implementation against an existing reliable source. You can use Julia, R, Python, or other languages to generate fixtures. To see how we do this, refer to these example scripts: [Python fixture script][python-fixtures], [Julia fixture script][julia-fixtures].
 
+<a name="test-cov"></a>
+
+## How can I generate the test coverage report for a specific package locally?
+
+To generate the test coverage report for a specific package, you can use the following commands:
+
+```bash
+$ make test-cov TESTS_FILTER=".*/math/base/special/floorn/.*"
+$ make view-cov
+```
+
+Modify the `TESTS_FILTER` argument to specify the package you want to test. The `view-cov` command will open the coverage report in your default web browser.
+
 <a name="uninitialized-variable"></a>
 
 ## I am facing a `Uninitialized variable` linting error in my C files, how can I fix it?