https://liamhammett.com/laravel-testing-css-selector-assertion-macros-D9o0YAQJ

README.md

You can register the mixin class in the register method of a Laravel service provider:

use Illuminate\Foundation\Testing\TestResponse;

TestResponse::mixin(TestResponseMixin::class);

TestResponseMixin.php

<?php

use DOMXPath;
use DOMDocument;
use DOMNodeList;
use Illuminate\Support\Str;
use Illuminate\Foundation\Testing\Assert as PHPUnit;
use Symfony\Component\CssSelector\CssSelectorConverter;

class TestResponseMixin
{
    public function getSelectorContents()
    {
        return function (string $selector): DOMNodeList {
            $dom = new DOMDocument();

            @$dom->loadHTML(
                mb_convert_encoding($this->getContent(), 'HTML-ENTITIES', 'UTF-8'),
                LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD
            );

            $xpath = new DOMXPath($dom);
            $converter = new CssSelectorConverter();
            $xpathSelector = $converter->toXPath($selector);

            $elements = $xpath->query($xpathSelector);

            return $elements;
        };
    }

    public function assertSelectorContains()
    {
        return function (string $selector, string $value) {
            $selectorContents = $this->getSelectorContents($selector);

            if (empty($selectorContents)) {
                PHPUnit::fail("The selector '{$selector}' was not found in the response.");
            }

            foreach ($selectorContents as $element) {
                if (Str::contains($element->textContent, $value)) {
                    PHPUnit::assertTrue(true);

                    return $this;
                }
            }

            PHPUnit::fail("The selector '{$selector}' did not contain the value '{$value}'.");

            return $this;
        };
    }

    public function assertSelectorsAllContain()
    {
        return function (string $selector, string $value) {
            $selectorContents = $this->getSelectorContents($selector);

            if (empty($selectorContents)) {
                PHPUnit::fail("The selector '{$selector}' was not found in the response.");
            }

            foreach ($selectorContents as $element) {
                if (!Str::contains($element->textContent, $value)) {
                    PHPUnit::fail("The selector '{$selector}' did not contain the value '{$value}'.");

                    return $this;
                }
            }

            PHPUnit::assertTrue(true);

            return $this;
        };
    }

    public function assertSelectorAttributeEquals()
    {
        return function (string $selector, string $attribute, $expected) {
            $nodes = $this->getSelectorContents($selector);

            if (count($nodes) === 0) {
                PHPUnit::fail("The selector '{$selector} was not found in the response.");

                return $this;
            }

            $firstNode = $nodes[0];

            PHPUnit::assertEquals($expected, $firstNode->getAttribute($attribute));

            return $this;
        };
    }
}

This is awesome. @imliam it would be great to have this available as a package.