public function testListDomesticLetterSizes() { $this->setMockResponse($this->client, array('postage/list_domestic_letter_sizes')); $response = $this->client->listDomesticLetterSizes(); $this->assertArrayHasKey('sizes', $response); $this->assertArrayHasKey('size', $response['sizes']); $this->assertCount(6, $response['sizes']['size']); }