test.js

const assert = require('assert');

const turing = require('./turing');

describe('Day 25: The Halting Problem', () => {
  it('should calculate diagnostic checksum', () => {
    const instructions =
      `
      Begin in state A.
      Perform a diagnostic checksum after 6 steps.

      In state A:
        If the current value is 0:
          - Write the value 1.
          - Move one slot to the right.
          - Continue with state B.
        If the current value is 1:
          - Write the value 0.
          - Move one slot to the left.
          - Continue with state B.

      In state B:
        If the current value is 0:
          - Write the value 1.
          - Move one slot to the left.
          - Continue with state A.
        If the current value is 1:
          - Write the value 1.
          - Move one slot to the right.
          - Continue with state A.
      `;

    const checksum = turing(instructions);

    assert.equal(checksum, 3);
  });
});