text: 'use strict';
  
  const assert = require('assert');
  
  const isFirstLetterCapitalized = require('../../lib/util/isFirstLetterCapitalized');
  
  describe('isFirstLetterCapitalized', () => {
    it('should return false for invalid input', () => {
      assert.equal(isFirstLetterCapitalized(), false);
      assert.equal(isFirstLetterCapitalized(null), false);
      assert.equal(isFirstLetterCapitalized(''), false);
    });
  
    it('should return false for uncapitalized string', () => {
      assert.equal(isFirstLetterCapitalized('isCapitalized'), false);
      assert.equal(isFirstLetterCapitalized('lowercase'), false);
    });
  
    it('should return true for capitalized string', () => {
      assert.equal(isFirstLetterCapitalized('IsCapitalized'), true);
      assert.equal(isFirstLetterCapitalized('UPPERCASE'), true);
    });
  });
  