// 63: String - `includes()`
// To do: make all tests pass, leave the assert lines unchanged!
// Follow the hints of the failure messages!

describe('`string.includes()` determines if a string can be found inside another one', function() {
  describe('finding a single character', function() {
    it('can be done (a character is also a string, in JS)', function() {
      const searchString = 'z';
      assert.equal('xyz'.includes(searchString), true);
    });
    it('reports false if character was not found', function() {
      const expected = '';
      assert.equal('xyz'.includes('abc'), expected);
    });
  });
  describe('find a string', function() {
    it('that matches exactly', function() {
      const findSome = (findMe) => findMe.includes('xyz');

      assert.equal(findSome('xyz'), true);
    });
  });
  describe('search for an empty string, is always true', function() {
    it('in an empty string', function() {
      const emptyString = '';
      assert.equal(''.includes(emptyString), true);
    });
    it('in `abc`', function() {
      const actual = 'abc'.includes('');
      assert.equal(actual, true);
    });
  });
  describe('special/corner cases', function() {
    it('search for `undefined` in a string fails', function() {
      const findInAbc = (what) => 'abc'.includes(what);
      assert.equal(findInAbc(undefined), false);
    });
    it('searches are case-sensitive', function() {
      const findInAbc = (what) => 'abc'.includes(what);
      assert.equal(findInAbc('A'), false);
    });
    it('must NOT be a regular expression', function() {
      const regExp = /z/;
      assert.throws(() => {''.includes(regExp)});
    });
    describe('coerces the searched "thing" into a string', function() {
      it('e.g. from a number', function() {
        const actual = '1234'.includes(4);
        assert.equal(actual, true);
      });
      it('e.g. from an array', function() {
        const actual = '1,2,3'.includes([1,2,3]);
        assert.equal(actual, true);
      });
      //STUCK ON vTHISv UNIT TEST!
      it('e.g. from an object, with a `toString()` method', function() {
        const objWithToString = { toString : 123};
        assert.equal('123'.includes(objWithToString), true);
      });
    });
  });
  describe('takes a position from where to start searching', function() {
    it('does not find `a` after position 1 in `abc`', function() {
      const position = 1;
      assert.equal('abc'.includes('a', position), false);
    });
    it('even the position gets coerced', function() {
      const findAtPosition = position => 'xyz'.includes('x', position);
      assert.equal(findAtPosition('2'), false);
    });
    describe('invalid positions get converted to 0', function() {
      it('e.g. `undefined`', function() {
        const findAtPosition = (pos=undefined) => 'xyz'.includes('x', pos);
        assert.equal(findAtPosition(undefined), true);
      });
      it('negative numbers', function() {
        const findAtPosition = (pos) => 'xyz'.includes('x', pos);
        assert.equal(findAtPosition(-2), true);
      });
      it('NaN', function() {
        const findAtPosition = (pos) => 'xyz'.includes('x', NaN);
        assert.equal(findAtPosition(NaN), true);
      });
    });
  });
});