Add test case for zero numerator with negative denominator in isProperFraction

Author: moses77-boop

implement-and-rewrite-tests/implement-tests-with-node-test/2-is-proper-fraction.test.js

@@ -9,6 +9,7 @@ import { isProperFraction } from "../implement/2-is-proper-fraction.js";
 test("Basic proper fraction", () => {
   assert.equal(isProperFraction(1, 2), true);
   assert.equal(isProperFraction(0, 5), true);
+  assert.equal(isProperFraction(0, -5), true);
   assert.equal(isProperFraction(-1, 2), true);
   assert.equal(isProperFraction(1, -2), true);
   assert.equal(isProperFraction(-1, -2), true);