Trait for testing with guzzle requests, use with https://gist.github.com/eduPHP/089ad67aa5980722c6cddd6353d0cf43

MocksGuzzle.php

<?php

namespace Tests;

use GuzzleHttp\Client;
use GuzzleHttp\Handler\MockHandler;
use GuzzleHttp\HandlerStack;
use GuzzleHttp\Psr7\Response as GuzzleResponse;
use Illuminate\Support\Arr;
use Tests\stubs\HttpClientStub;

trait MocksGuzzle
{
    protected function fakeApiResponse(string $name, array $replace = [], $raw = false)
    {
        if (file_exists($file = base_path("/tests/apiResponses/{$name}.json"))) {
            $content = file_get_contents($file);
        } elseif (file_exists($file = base_path("/tests/apiResponses/{$name}.xml"))) {
            $content = file_get_contents($file);
        } elseif (file_exists($file = base_path("/tests/apiResponses/{$name}"))) {
            $content = file_get_contents($file);
        } else {
            $content = $name;
        }

        foreach ($replace as $key => $value) {
            $content = preg_replace("[\{{$key}\}]", $value, $content);
        }

        return $raw ? $content : json_decode($content, true);
    }

    public function fakeGuzzleResponse($response, $status = 200): MockHandler
    {
        $response = Arr::wrap($response);
        $status = Arr::wrap($status);
        $guzzleResponse = [];
        foreach ($response as $i => $item) {
            if ($item instanceof GuzzleResponse) {
                $guzzleResponse[] = $item;
            } else {
                $guzzleResponse[] = new GuzzleResponse($status[$i] ?? 200, [], is_array($item) ?
                    json_encode($item) :
                    $item
                );
            }
        }

        $mock = new MockHandler($guzzleResponse);

        $this->instance(Client::class, new HttpClientStub(['handler' => HandlerStack::create($mock)]));

        return $mock;
    }

    public function assertGuzzleHasFormParams(array|string $expectedParam, $n = 0)
    {
        foreach (Arr::wrap($expectedParam) as $key => $param) {
            if (is_numeric($key) && !isset(HttpClientStub::$options[$n]['form_params'][$param])) {
                $this->fail("Failed asserting that Guzzle has sent '{$param}' param.");
            } else if (!is_numeric($key) && !isset(HttpClientStub::$options[$n]['form_params'][$key])) {
                $this->fail("Failed asserting that Guzzle has sent '{$key}' param.");
            } else if (!is_numeric($key) && isset(HttpClientStub::$options[$n]['form_params'][$key]) && HttpClientStub::$options[$n]['form_params'][$key] !== $param) {
                $this->fail("Failed asserting that Guzzle param '{$key}' is equals to '{$param}'.");
            }
            $this->addToAssertionCount(1);
        }
    }

    public function assertGuzzleUrlContains(array|string $expectedParam, $n = 0)
    {
        foreach (Arr::wrap($expectedParam) as $param) {
            $this->assertStringContainsString(
                $param,
                HttpClientStub::$uri[$n]
            );
        }
    }
}