Kumite

const chai = require("chai");
const assert = chai.assert;
chai.config.truncateThreshold=0;

describe("factorial", function() {
  it("should work with positive", function() {
    assert.strictEqual(factorial( 1 ), 1);
    assert.strictEqual(factorial( 2 ), 2);
    assert.strictEqual(factorial( 3 ), 6);
    assert.strictEqual(factorial( 4 ), 24);
    assert.strictEqual(factorial( 5 ), 120);
    assert.strictEqual(factorial( 6 ), 720);
    assert.strictEqual(factorial( 7 ), 5040);
    assert.strictEqual(factorial( 8 ), 40320);
    assert.strictEqual(factorial( 9 ), 362880);
    assert.strictEqual(factorial( 10 ), 3628800);
  });
  
  it("should work with negative", function() {
    assert.strictEqual(factorial( -1 ), -1);
    assert.strictEqual(factorial( -2 ), 2);
    assert.strictEqual(factorial( -3 ), -6);
    assert.strictEqual(factorial( -4 ), 24);
    assert.strictEqual(factorial( -5 ), -120);
    assert.strictEqual(factorial( -6 ), 720);
  });
  
  it("should work with zero", function() {
    assert.strictEqual(factorial(0), 1);
  });
});