@@ -0,0 +1,87 @@
+package option
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/yuin/goldmark"
+)
+
+func TestOptionExtension(t *testing.T) {
+	markdown := goldmark.New(
+		goldmark.WithExtensions(
+			New(),
+		),
+	)
+
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:  "basic option reference",
+			input: "{option}`initialHashedPassword`",
+			expected: "<p><a class=\"option\" href=\"/?query=initialHashedPassword\">" +
+				"<code>initialHashedPassword</code></a></p>\n",
+		},
+		{
+			name:  "option reference in sentence",
+			input: "You can set {option}`initialHashedPassword` to configure the initial password.",
+			expected: "<p>You can set <a class=\"option\" href=\"/?query=initialHashedPassword\">" +
+				"<code>initialHashedPassword</code></a> to configure the initial password.</p>\n",
+		},
+		{
+			name:  "multiple option references",
+			input: "Both {option}`initialHashedPassword` and {option}`passwordFile` can be used.",
+			expected: "<p>Both <a class=\"option\" href=\"/?query=initialHashedPassword\">" +
+				"<code>initialHashedPassword</code></a> and <a class=\"option\" href=\"/?query=passwordFile\">" +
+				"<code>passwordFile</code></a> can be used.</p>\n",
+		},
+		{
+			name:     "incomplete option reference - no closing backtick",
+			input:    "{option}`missingBacktick",
+			expected: "<p>{option}`missingBacktick</p>\n",
+		},
+		{
+			name:     "incomplete option reference - empty option name",
+			input:    "{option}``",
+			expected: "<p>{option}``</p>\n",
+		},
+		{
+			name:  "option reference with code block",
+			input: "{option}`config` is set in `config.nix`",
+			expected: "<p><a class=\"option\" href=\"/?query=config\"><code>config</code></a> " +
+				"is set in <code>config.nix</code></p>\n",
+		},
+		{
+			name:  "option reference with HTML-like content",
+			input: "{option}`users.users.<name>.hashedPassword`",
+			expected: "<p><a class=\"option\" href=\"/?query=users.users.%3Cname%3E.hashedPassword\">" +
+				"<code>users.users.&lt;name&gt;.hashedPassword</code></a></p>\n",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			var buf bytes.Buffer
+			if err := markdown.Convert([]byte(test.input), &buf); err != nil {
+				t.Fatalf("Failed to convert markdown: %v", err)
+			}
+
+			if got := buf.String(); got != test.expected {
+				t.Errorf("Expected:\n%q\nGot:\n%q", test.expected, got)
+			}
+		})
+	}
+}
+
+func TestOptionNodeKind(t *testing.T) {
+	n := &Node{}
+	if kind := n.Kind(); kind != KindOption {
+		t.Errorf("Expected node kind %v, got %v", KindOption, kind)
+	}
+	if !n.Inline() {
+		t.Error("Expected node to be inline")
+	}
+}