Example of writing a unit test that has two PDO db calls that need to return two different results

gistfile1.php

<?php

// Let's say we have two different result sets
$result_set = array();
$result_set[0] = array(
  array(
    'id' => 1,
    'name' => 'Foo',
    'type' => 'Bar',
    'status' => 'valid'
  )
);
$result_set[1] = array(
  array(
    'id' => 2,
    'name' => 'Fizz',
    'type' => 'Buzz',
    'status' => 'valid'
  ),
  array(
    'id' => 3,
    'name' => 'Alpha',
    'type' => 'Greek',
    'status' => 'invalid'
  )
);

// I always use stdClass as stand-in for PDO objects in my tests
$db = $this->getMockBuilder('stdClass')->setMethods(array('fetchAll'))->getMock();

// On the first call to fetchAll() return our first result set
$db->expects($this->at(0))->method('fetchAll')->will($this->returnValue($result_set[0]));

// On the second call, return the second result set
$db->expects($this->at(1))->method('fetchAll')->will($this->returnValue($result_set[1]));

// Inject the DB object in as a dependency
$widget = new Widget($db);

// First DB query happens, return what we expect as the first result set
$tmp = $widget->frobagize();

// Second query happens, doing a query that should return the second result set
$results = $widget->congeal($tmp);

// Do your assertions are whatever you need to do