Snippet from helloTestableTest.php

helloTestableTest.php

<?php

    public function testEchoCss()
    {
        \WP_Mock::userFunction('is_rtl', array(
            'return_in_order' => array(true, false),
        ));

        $dummy = new \stdClass();
        $hello = new helloTestable($dummy);

        $this->expectOutputRegex('/.*float: left*./');
        $hello->echoCss();

        $this->expectOutputRegex('/.*float: right*./');
        $hello->echoCss();
    }