chore: Add psalm and cs-checker

Author: keelerm84

.php-cs-fixer.php

@@ -0,0 +1,15 @@
+<?php
+
+$finder = PhpCsFixer\Finder::create()->in(__DIR__);
+
+$config = new PhpCsFixer\Config();
+return $config
+    ->setFinder($finder)
+    ->setUsingCache(true)
+    ->setRules([
+        '@PSR2' => true,
+        'blank_line_after_opening_tag' => true,
+        'ordered_imports' => true,
+        'no_unused_imports' => true,
+        'array_syntax' => ['syntax' => 'short'],
+    ]);

Makefile

@@ -0,0 +1,19 @@
+.PHONY: help
+help: #! Show this help message
+	@echo 'Usage: make [target] ... '
+	@echo ''
+	@echo 'Targets:'
+	@grep -h -F '#!' $(MAKEFILE_LIST) | grep -v grep | sed 's/:.*#!/:/' | column -t -s":"
+
+.PHONY: test
+test: #! Run unit tests
+	php -d xdebug.mode=coverage vendor/bin/phpunit
+
+.PHONY: coverage
+coverage: #! Run unit tests with test coverage
+	php -d xdebug.mode=coverage vendor/bin/phpunit
+
+.PHONY: lint
+lint: #! Run quality control tools (e.g. psalm)
+	./vendor/bin/psalm --no-cache
+	composer cs-check

composer.json

@@ -21,10 +21,13 @@
     ],
     "require": {
         "php": ">=8.1",
-        "launchdarkly/server-sdk": ">=6.4.0 <7.0.0"
+        "launchdarkly/server-sdk": ">=6.3.0 <7.0.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9"
+        "friendsofphp/php-cs-fixer": "^3.68",
+        "phpunit/php-code-coverage": "^9",
+        "phpunit/phpunit": "^9",
+        "vimeo/psalm": "^5"
     },
     "autoload": {
         "psr-4": {
@@ -38,5 +41,9 @@
     },
     "config": {
         "sort-packages": true
+    },
+    "scripts": {
+        "cs-check": "vendor/bin/php-cs-fixer fix --diff --dry-run --verbose --config=.php-cs-fixer.php",
+        "cs-fix": "vendor/bin/php-cs-fixer fix --diff --verbose --config=.php-cs-fixer.php"
     }
 }

psalm.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<psalm
+    errorLevel="2"
+    resolveFromConfigFile="true"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="https://getpsalm.org/schema/config"
+    xsi:schemaLocation="https://getpsalm.org/schema/config vendor/vimeo/psalm/config.xsd"
+>
+    <projectFiles>
+        <directory name="src" />
+        <ignoreFiles>
+            <directory name="vendor" />
+        </ignoreFiles>
+    </projectFiles>
+</psalm>