Test the update of a field instance.
function testUpdateFieldInstance() {
field_create_instance($this->instance_definition);
// Check that basic changes are saved.
$instance = field_read_instance('test_entity', $this->instance_definition['field_name'], $this->instance_definition['bundle']);
$instance['required'] = !$instance['required'];
$instance['label'] = $this
->randomName();
$instance['description'] = $this
->randomName();
$instance['settings']['test_instance_setting'] = $this
->randomName();
field_update_instance($instance);
$instance_new = field_read_instance('test_entity', $this->instance_definition['field_name'], $this->instance_definition['bundle']);
$this
->assertEqual($instance['required'], $instance_new['required'], '"required" change is saved');
$this
->assertEqual($instance['label'], $instance_new['label'], '"label" change is saved');
$this
->assertEqual($instance['description'], $instance_new['description'], '"description" change is saved');
// TODO: test failures.
}