diff --git a/test/isPromiseLike.test.js b/test/isPromiseLike.test.js
index eabc7fb80..7bf5b9af3 100644
--- a/test/isPromiseLike.test.js
+++ b/test/isPromiseLike.test.js
@@ -16,3 +16,6 @@ test('Returns true for a promise-like object', () => {
 test('Returns false for an empty object', () => {
   expect(isPromiseLike({})).toBeFalsy();
 });
+test('Returns false for a normal function', () => {
+  expect(isPromiseLike(Math.max)).toBeFalsy();
+});
diff --git a/test/mostPerformant.test.js b/test/mostPerformant.test.js
index 28f2b46dd..ca61d403f 100644
--- a/test/mostPerformant.test.js
+++ b/test/mostPerformant.test.js
@@ -4,3 +4,9 @@ const {mostPerformant} = require('./_30s.js');
 test('mostPerformant is a Function', () => {
   expect(mostPerformant).toBeInstanceOf(Function);
 });
+test('mostPerformant returns a number', () => {
+  expect(typeof mostPerformant([Math.max, Math.min])).toBe('number');
+});
+test('mostPerformant returns a number', () => {
+  expect(typeof mostPerformant([Math.max, Math.min], 10)).toBe('number');
+});