gistfile1.php

<?php

namespace foo {
    
    interface client 
    {
        
        public function execute($query, array $params);
        
    }

    class api 
    {
        
        protected $client;
        
        public function __construct(client $client)
        {
            $this->client = $client;
        }
        
        public function doSomething($query) 
        {
            $datas = $this->client->execute($query, array('foo' => 'bar'));

            return true;
        }
    }
}

namespace tests\units\foo {

    use mageekguy\atoum as atoum;

    use foo\api as testedClass;

    class api extends atoum\test
    {

        public function testdoSomething()
        {
            $this
                ->if($client = new \mock\foo\client())
                ->and($client->getMockController()->execute = array(42))
                ->and($api = new testedClass($client))
                ->then
                    ->boolean($api->doSomething('str'))->isTrue()
                    ->mock($client)
                        ->call('execute')->withArguments('some query')->once()
                    ->boolean($api->doSomething('some query'))->isTrue()
            ;
            
        }
    }

}