update unit tests for gcd function

- add more tests to cover edge cases and different scenarios
- delete incorrect test (gcd(1, 0) = 0)

Author: os-moussao

test/ts/algorithms/math/gcd.spec.ts

@@ -3,14 +3,26 @@ import { expect } from 'chai';
 import { gcd } from '../../../../src/ts/index';
 
 describe('GCD', () => {
+  it('returns the correct GCD for positive numbers', () => {
+    expect(gcd(8, 12)).to.equal(4);
+    expect(gcd(15, 25)).to.equal(5);
+    expect(gcd(21, 28)).to.equal(7);
+  });
+
+  it('returns the correct GCD for negative numbers', () => {
+    expect(gcd(-8, 12)).to.equal(4);
+    expect(gcd(15, -25)).to.equal(5);
+    expect(gcd(-21, -28)).to.equal(7);
+  });
 
-  it('returns the gcd between two numbers', () => {
+  it('returns the correct GCD when one of the numbers is 0', () => {
+    expect(gcd(0, -12)).to.equal(12);
+    expect(gcd(15, 0)).to.equal(15);
+  });
 
-    expect(gcd(1, 0)).to.equal(0);
-    expect(gcd(1, 1)).to.equal(1);
-    expect(gcd(2, 2)).to.equal(2);
-    expect(gcd(2, 4)).to.equal(2);
-    expect(gcd(2, 3)).to.equal(1);
-    expect(gcd(10, 1000)).to.equal(10);
+  it('returns 1 for co-prime numbers', () => {
+    expect(gcd(7, 22)).to.equal(1);
+    expect(gcd(11, 28)).to.equal(1);
+    expect(gcd(9, 16)).to.equal(1);
   });
 });