Testing flows

A flow returns its receipt, so a test runs the flow and asserts on what the receipt says. No mocks of the flow itself, and the assertions read like the business rules.

Test the whole flow

Build the flow in one place (CheckoutFlow) and use it in every test:

<?php

namespace Tests\Feature;

use CheckoutFlow;
use Keaton\PipeDream\Receipt;
use Order;
use Tests\TestCase;

class CheckoutFlowTest extends TestCase
{
    private function order(array $overrides = []): Order
    {
        return new Order(...$overrides + [
            'id' => 'ord_1',
            'items' => [['sku' => 'cap-nvy', 'name' => 'Navy cap', 'price' => 25.00]],
            'shippingAddress' => '500 Congress Ave, Austin',
            'shippingCountry' => 'US',
            'billingCountry' => 'US',
        ]);
    }

    private function checkout(Order $order): Receipt
    {
        return CheckoutFlow::build()->subject($order)->sendIt()->receipt();
    }

    public function test_a_clean_order_is_placed(): void
    {
        $receipt = $this->checkout($this->order());

        $this->assertSame('Placed', $receipt->summary());
        $this->assertSame(Receipt::COMPLETED, $receipt->outcome());
    }

    public function test_two_fraud_signals_hold_the_order_and_nothing_is_charged(): void
    {
        $receipt = $this->checkout($this->order(['billingCountry' => 'CA', 'cardsTriedRecently' => 4]));

        $this->assertSame('On hold: Two or more fraud signals', $receipt->summary());
        $this->assertSame(
            'Held for review: Two or more fraud signals',
            $receipt->hubs()->firstWhere(fn ($hub) => $hub->name() === 'Charge')->skipReason(),
        );
    }

    public function test_a_trusted_customer_skips_the_fraud_screen(): void
    {
        $receipt = $this->checkout($this->order(['trustedCustomer' => true]));

        $this->assertSame(
            'Trusted customer',
            $receipt->hubs()->firstWhere(fn ($hub) => $hub->name() === 'Fraud screen')->skipReason(),
        );
    }

    public function test_an_out_of_stock_item_stops_the_flow_at_validation(): void
    {
        $receipt = $this->checkout($this->order([
            'items' => [['sku' => 'sold-out', 'name' => 'Poster', 'price' => 40.00]],
        ]));

        $this->assertTrue($receipt->wasStopped());
        $this->assertSame(['Out of stock: Poster'], $receipt->steps()->last()->messages()->all());
        $this->assertSame(['Validate the order'], $receipt->hubs()->map->name()->all());
    }
}

These extend your application's own Tests\TestCase, and run as they are in PHPUnit or inside a Pest it().

Test one rule

Run the rule alone in a hub, as on Rules, and assert on its result: $envelope->get(CheckCardVelocity::class) is PipeRule::FAIL. A rule is resolved through the container, so bind a fake dependency (a Warehouse that says everything is sold out) before the run.

What to assert on

No side effects

A flow writes nothing outside your code unless a persist strategy is set or bound. In tests, leave it unbound, or call ->persistLogs(false) to make it explicit.

Next: Events.