diff --git a/src/generic/__test__/arithmetic.spec.js b/src/generic/__test__/arithmetic.spec.js
index 17752af..f1d6043 100644
--- a/src/generic/__test__/arithmetic.spec.js
+++ b/src/generic/__test__/arithmetic.spec.js
@@ -4,5 +4,8 @@ import math from '#nanomath'
 describe('generic arithmetic', () => {
    it('squares anything', () => {
       assert.strictEqual(math.square(7), 49)
+      assert.strictEqual(
+         math.square.resolve([math.types.Number]).returns,
+         math.types.Number)
    })
 })