added unit tests

tests/check-coverage.php

@@ -0,0 +1,60 @@
+#!/usr/bin/env php
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Fail CI when line coverage falls below the configured floor.
+ * Usage: php tests/check-coverage.php [minPercent]
+ */
+
+$min = isset($argv[1]) ? (float)$argv[1] : 40.0;
+$root = dirname(__DIR__);
+
+$envPrefix = '';
+if (extension_loaded('xdebug') && !extension_loaded('pcov')) {
+    // Xdebug 3 defaults to develop mode; PHPUnit needs coverage mode.
+    $envPrefix = 'XDEBUG_MODE=coverage ';
+}
+
+$cmd = sprintf(
+    '%s%s %s/vendor/bin/phpunit --coverage-text --colors=never 2>&1',
+    $envPrefix,
+    escapeshellarg(PHP_BINARY),
+    escapeshellarg($root)
+);
+
+$output = [];
+exec($cmd, $output, $exitCode);
+echo implode("\n", $output) . "\n";
+
+if ($exitCode !== 0) {
+    exit($exitCode);
+}
+
+$linesPct = null;
+foreach ($output as $line) {
+    // PHPUnit 11 / Xdebug: "Lines:   25.33% (1484/5859)"
+    if (preg_match('/^\s*Lines:\s+([\d.]+)%\s+\(/', $line, $m)) {
+        $linesPct = (float)$m[1];
+        break;
+    }
+    // PCOV / older format: "Lines:   1484/5859 (25.33%)"
+    if (preg_match('/^\s*Lines:\s+[\d.]+\/\d+\s+\(\s*([\d.]+)%/', $line, $m)) {
+        $linesPct = (float)$m[1];
+        break;
+    }
+}
+
+if ($linesPct === null) {
+    fwrite(STDERR, "Could not parse coverage summary. Is PCOV or Xdebug enabled?\n");
+    exit(1);
+}
+
+if ($linesPct < $min) {
+    fwrite(STDERR, sprintf("Line coverage %.2f%% is below minimum %.2f%%\n", $linesPct, $min));
+    exit(1);
+}
+
+fwrite(STDERR, sprintf("Line coverage %.2f%% meets minimum %.2f%%\n", $linesPct, $min));
+exit(0);