feat: add unit tests

t/06-code.t

@@ -0,0 +1,35 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use Test::More tests => 5;
+use MarkdownParser;
+
+my $parser = MarkdownParser->new();
+
+is(
+    $parser->parse("`inline code`"),
+    "<p><code>inline code</code></p>\n",
+    "Inline code"
+);
+is(
+    $parser->parse("Text with `code` in it"),
+    "<p>Text with <code>code</code> in it</p>\n",
+    "Inline code in text"
+);
+is(
+    $parser->parse("```\ncode block\n```"),
+    "<pre><code>\ncode block\n</code></pre>\n",
+    "Code block"
+);
+is(
+    $parser->parse("```\nline 1\nline 2\nline 3\n```"),
+    "<pre><code>\nline 1\nline 2\nline 3\n</code></pre>\n",
+    "Multi-line code block"
+);
+is(
+    $parser->parse("```\n```"),
+    "<pre><code>\n</code></pre>\n",
+    "Empty code block"
+);
+