add phpunit config file

.gitignore

@@ -4,3 +4,4 @@ vendor
 .idea
 .DS_Store
 .php-cs-fixer.cache
+.phpunit.result.cache

composer.json

@@ -25,8 +25,8 @@
     "squizlabs/php_codesniffer": "^3.11"
   },
   "scripts": {
-    "test": "php vendor/bin/phpunit --bootstrap tests/bootstrap.php  tests/",
-    "check-syntax": "./bin/check-php-syntax",
+    "test": "vendor/bin/phpunit",
+    "check-syntax": "bin/check-php-syntax",
     "lint": "vendor/bin/phpcs -n -s",
     "fmt": "vendor/bin/phpcbf"
   }

phpunit.xml.dist

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<!-- https://docs.phpunit.de/en/9.6/ -->
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         colors="true"
+         bootstrap="tests/bootstrap.php"
+         convertDeprecationsToExceptions="true"
+>
+    <php>
+        <ini name="display_errors" value="1" />
+        <ini name="error_reporting" value="-1" />
+        <server name="SHELL_VERBOSITY" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Koko Analytics Test Suite">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </coverage>
+
+</phpunit>

tests/bootstrap.php

@@ -2,9 +2,7 @@
 
 // phpcs:disable PSR1.Files.SideEffects
 
-require __DIR__ . '/../autoload.php';
-
-define('KOKO_ANALYTICS_PLUGIN_FILE', '../koko-analytics.php');
+require dirname(__DIR__) . '/koko-analytics.php';
 
 function apply_filters($a, $b, $prio = 10, $args = 2)
 {
@@ -21,14 +19,15 @@ function add_shortcode($a, $b)
 }
 function number_format_i18n($number, $decimals = 0)
 {
-    return $number;
+    return number_format($number, $decimals);
 }
 function register_activation_hook($a, $b)
 {
 }
 function update_option($a, $b, $c = false)
 {
 }
-function get_option($a, $b, $c = false)
+function get_option($a, $b = null)
 {
+    return $b;
 }