Add more tests

Author: JBlond

tests/Diff/LargeInputTest.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Tests\Diff;
+
+use PHPUnit\Framework\TestCase;
+use jblond\Diff;
+use jblond\Diff\Renderer\Text\Unified;
+
+class LargeInputTest extends TestCase
+{
+    public function testLargeInputDoesNotCrash(): void
+    {
+        $a = str_repeat("A\n", 2000);
+        $b = str_repeat("B\n", 2000);
+        $diff = new Diff($a, $b);
+        $output = $diff->render(new Unified());
+        $this->assertNotEmpty($output);
+    }
+}