gistfile1.txt

$ composer exec phpunit test/SampleTest.php
PHPUnit 5.5.5 by Sebastian Bergmann and contributors.

..                                                                  2 / 2 (100%)

Time: 10 ms, Memory: 4.00MB

OK (2 tests, 6 assertions)






$ composer exec phpunit
PHPUnit 5.5.5 by Sebastian Bergmann and contributors.

W..                                                                 3 / 3 (100%)

Time: 50 ms, Memory: 4.00MB

There was 1 warning:

1) Warning
No tests found in class "PHPUnit\Framework\TestCase".

WARNINGS!
Tests: 3, Assertions: 6, Warnings: 1.

phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>

<phpunit bootstrap="vendor/autoload.php">
  <testsuites>
    <testsuite name="foo">
      <directory>test</directory>
    </testsuite>
  </testsuites>
</phpunit>