PHPUnit - Use $this or self for static methods?

Question

I don\'t want to write a long text, because it is a short question. PHPUnit tests contain several methods that are static. For example all those \\PHPUnit\\Framework\\Assert

Answer 1

PHPUnit 4.8.9: vendor/phpunit/phpunit/src/Framework/Assert.php:

/**
 * Asserts that a condition is true.
 *
 * @param bool   $condition
 * @param string $message
 *
 * @throws PHPUnit_Framework_AssertionFailedError
 */
public static function assertTrue($condition, $message = '')
{
    self::assertThat($condition, self::isTrue(), $message);
}

Technically static::assertTrue() is correct, but the common usage of the assert methods is $this->assertTrue().