Setting preconditions

Last updated at 08 December 2019 | Published at 04 March 2018

Often you’ll want to set up preconditions for tests. These are events recorded prior to the interaction you want to test in the current scenario. This can be provided using the given method. This method receives one or more events:

class SigningUp extends SignUpProcessTestCase
{
    /**
     * @test
     */
    public function signing_up_works()
    {
        $this->given(
            new SignUpWasInitiated(),
            new EmailWasSpecifiedForSignUp('[email protected]')
        )->when(
            new FinalizeSignUpProcess()
        )->then(
            new SignUpWasFinalized()
        );
    } 
}

In our aggregate root this may be translated to:

<?php

class SignUpProcess implements AggregateRoot
{
    use AggregateRootBehaviour;

    private $singupWasInitiated = false;
    private $emailUsed = null;

    public static function initiate(SignupId $id)
    {
        $process = new static($id);
        $process->recordThat(new SignUpWasInitiated());
    }

    public function applySignUpWasInitiated(): void
    {
        // handle
    }

    public function specifyEmailAddress(string $email): void
    {
        $this->recordThat(new EmailWasSpecifiedForSignUp($email));
    }

    public function applyEmailWasSpecifiedForSignUp(EmailWasSpecifiedForSignUp $event): void
    {
        $this->emailUsed = $event->email();
    }

    public function finalize(): void
    {
        if ( ! is_string($this->emaiUsed)) {
            throw NoEmailWasSpecifiedDuringSignup::forProcess($this->aggregateRootId);
        }

        $this->recordThat(new SignUpWasFinalized());
    }
}
Frank de Jonge

EventSauce is a project by Frank de Jonge.