@@ -0,0 +1,78 @@
+package variable
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/yuin/goldmark"
+)
+
+func TestVarExtension(t *testing.T) {
+	markdown := goldmark.New(
+		goldmark.WithExtensions(
+			New(),
+		),
+	)
+
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "basic variable reference",
+			input:    "{var}`pkgs.virtualbox`",
+			expected: "<p><var>pkgs.virtualbox</var></p>\n",
+		},
+		{
+			name:     "variable reference in sentence",
+			input:    "Use {var}`nixpkgs.lib.attrsets` to manipulate attribute sets.",
+			expected: "<p>Use <var>nixpkgs.lib.attrsets</var> to manipulate attribute sets.</p>\n",
+		},
+		{
+			name:  "multiple variable references",
+			input: "Both {var}`config.services.nginx` and {var}`config.services.postgresql` define service configurations.",
+			expected: "<p>Both <var>config.services.nginx</var> and <var>" +
+				"config.services.postgresql</var> define service configurations.</p>\n",
+		},
+		{
+			name:     "incomplete variable reference - no closing backtick",
+			input:    "{var}`MISSING_BACKTICK",
+			expected: "<p>{var}`MISSING_BACKTICK</p>\n",
+		},
+		{
+			name:     "incomplete variable reference - empty variable name",
+			input:    "{var}``",
+			expected: "<p>{var}``</p>\n",
+		},
+		{
+			name:  "variable reference with code block",
+			input: "Set {var}`pkgs.hello` in your `configuration.nix` file.",
+			expected: "<p>Set <var>pkgs.hello</var> " +
+				"in your <code>configuration.nix</code> file.</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 TestVarNodeKind(t *testing.T) {
+	n := &Node{}
+	if kind := n.Kind(); kind != KindVar {
+		t.Errorf("Expected node kind %v, got %v", KindVar, kind)
+	}
+	if !n.Inline() {
+		t.Error("Expected node to be inline")
+	}
+}