Faker\Generator::getFormatter PHP Method

    public function getFormatter($formatter)
    {
        if (isset($this->formatters[$formatter])) {
            return $this->formatters[$formatter];
        }
        foreach ($this->providers as $provider) {
            if (method_exists($provider, $formatter)) {
                $this->formatters[$formatter] = array($provider, $formatter);
                return $this->formatters[$formatter];
            }
        }
        throw new \InvalidArgumentException(sprintf('Unknown formatter "%s"', $formatter));
    }

 /**
  * @expectedException InvalidArgumentException
  */
 public function testGetFormatterThrowsExceptionOnIncorrectFormatter()
 {
     $generator = new Generator();
     $provider = new FooProvider();
     $generator->addProvider($provider);
     $generator->getFormatter('barFormatter');
 }