1 + 1 = 2 testing antipattern

test.ts

// Avoid generating expected results as they are not testing your logic independently
describe('1+1=2 testing antipattern', () => {
  describe('add', () => {
    const add = (a: number, b: number): number => a + b;
    const expected = 1 + 1;

    it('should add two numbers', () => {
      // This is testing two sets of logic, and doesnt guarantee the correctness of the function
      // as the output of expected could also be wrong
      expect(add(1, 1)).toEqual(expected);

      // This is actually testing that the add function is correct
      expect(add(1, 1)).toEqual(2);
    });
  });
});