$ composer update
```
-#### Install and enable Xdebug to generate PHPUnit coverage reports
+#### Install Xdebug
-See http://xdebug.org/docs/install
+Xdebug must be installed and enable for PHPUnit to generate coverage reports. See http://xdebug.org/docs/install.
```bash
# for Debian-based distributions
```
Then add the following line to `/etc/php/php.ini`:
+
```ini
zend_extension=xdebug.so
```
Run `make test` and ensure tests return `OK`. If tests return failures, refer to PHPUnit messages and fix your code/tests accordingly.
-
-#### Test results and coverage
-
-By default, PHPUnit will run all suitable tests found under the `tests` directory.
-
-Each test has 3 possible outcomes:
+By default, PHPUnit will run all suitable tests found under the `tests` directory. Each test has 3 possible outcomes:
- `.` - success
- `F` - failure: the test was run but its results are invalid