drupal_composer_builder/phpunit.xml

<?xml version="1.0" encoding="UTF-8"?>
<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
         colors="true"
         verbose="true"
         cacheResultFile=".phpunit.cache/test-results"
         failOnRisky="true"
         failOnWarning="true">
  <testsuites>
    <testsuite name="unit">
      <directory>tests</directory>
    </testsuite>
  </testsuites>

  <coverage cacheDirectory=".phpunit.cache/code-coverage"
            processUncoveredFiles="true"
            ignoreDeprecatedCodeUnits="true">
    <include>
      <directory suffix=".php">src</directory>
    </include>

    <exclude>
      <directory>vendor</directory>
    </exclude>
  </coverage>

  <php>
    <ini name="precision" value="14"/>
    <ini name="serialize_precision" value="14"/>

    <const name="PHPUNIT_TESTSUITE" value="true"/>
  </php>
</phpunit>