To provide behavioural test infrastructure, add install Behat and add first test

php/behat.yml

@@ -0,0 +1,9 @@
+default:
+
+    suites:
+
+        servicelevel:
+            paths:    [ '%paths.base%/tests/behat/feature_files' ]
+            filters:
+                tags: ~@wip
+            contexts: [ 'BehatTests\ServiceLevelContext' ]

php/composer.json

@@ -7,6 +7,7 @@
     },
     "require-dev": {
         "approvals/approval-tests": "dev-Main",
+        "behat/behat": "^3.14",
         "phpunit/phpunit": "^9.5",
         "phpstan/phpstan": "^1.9",
         "phpstan/phpstan-phpunit": "^1.3",
@@ -20,11 +21,12 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "Tests\\": "tests/"
+            "Tests\\": "tests/",
+            "BehatTests\\": "tests/behat/contexts/"
         }
     },
     "scripts": {
-        "tests": "phpunit",
+        "tests": "./vendor/bin/phpunit; ./vendor/bin/behat;",
         "test-coverage": "phpunit --coverage-html build/coverage",
         "check-cs": "ecs check",
         "fix-cs": "ecs check --fix",

php/tests/behat/contexts/ServiceLevelContext.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace BehatTests;
+
+use Behat\Behat\Tester\Exception\PendingException;
+use Behat\Behat\Context\Context;
+use Behat\Step\Given;
+use Behat\Step\Then;
+use Behat\Step\When;
+use GildedRose\Item;
+use GildedRose\GildedRose;
+use PHPUnit\Framework\Assert;
+
+class ServiceLevelContext implements Context
+{
+    private Item $item;
+    private GildedRose $gildedRose;
+
+    #[Then('I should see :expectedOutput')]
+    public function iShouldSee(string $expectedOutput): void
+    {
+        Assert::assertEquals([$expectedOutput], $this->result);
+    }
+
+    #[Given('an item with a sell_in of :initialellIn and a quality of :initialQuality')]
+    public function anItemWithASellInOfAndAQualityOf(int $initialellIn, int $initialQuality)
+    {
+        $this->item = new Item('foo', $initialellIn, $initialQuality);
+        $this->gildedRose = new GildedRose([$this->item]);
+    }
+
+    #[When('I update the quality')]
+    public function iUpdateTheQuality()
+    {
+        $this->gildedRose->updateQuality();
+    }
+
+    #[Then('the item should have a quality of :expectedQuality')]
+    public function theItemShouldHaveAQualityOf($expectedQuality)
+    {
+        Assert::assertEquals($expectedQuality, $this->item->quality);
+    }
+
+    #[When('I update the quality :noOfDays times')]
+    public function iUpdateTheQualityTimes(int $noOfDays)
+    {
+        for ($i = 0; $i < $noOfDays; $i++) {
+            $this->gildedRose->updateQuality();
+        }
+    }
+}

php/tests/behat/feature_files/default-quality-degradation.feature

@@ -0,0 +1,16 @@
+Feature: Default quality degradation
+  In order to keep track of item quality
+  As a shopkeeper
+  I want to see the quality of an item decrease by 1 each day
+
+
+  Scenario: Single quality update
+    Given an item with a sell_in of 20 and a quality of 20
+    When I update the quality
+    Then the item should have a quality of 19
+
+
+  Scenario: Quality updates over multiple days
+    Given an item with a sell_in of 20 and a quality of 20
+    When I update the quality 5 times
+    Then the item should have a quality of 15