diff --git a/token/token_test.go b/token/token_test.go
new file mode 100644
index 0000000..05045b0
--- /dev/null
+++ b/token/token_test.go
@@ -0,0 +1,25 @@
+package token
+
+import "testing"
+
+func TestTypeString(t *testing.T) {
+	tests := []struct {
+		typ  Type
+		want string
+	}{
+		{Number, "Number"},
+		{Plus, "+"},
+		{Minus, "-"},
+		{Star, "*"},
+		{Slash, "/"},
+		{LParen, "("},
+		{RParen, ")"},
+		{EOF, "EOF"},
+		{Type(99), "Unknown(99)"},
+	}
+	for _, tc := range tests {
+		if got := tc.typ.String(); got != tc.want {
+			t.Errorf("Type(%d).String() = %q, want %q", int(tc.typ), got, tc.want)
+		}
+	}
+}