code: function notStrictEqual(actual, expected, message) {
      if (actual !== expected) {
        this.pass(message);
      }
      else {
        this.fail({
          actual: actual,
          expected: expected,
          message: message,
          operator: "!=="
        })
      }
    }
docs: The strict non-equality assertion tests for strict inequality, as
  determined by `!==`.
  @example
  assert.notStrictEqual(null, undefined, "`null` is not `undefined`");