Error on XHR stub if resonse json only contains a number or boolean

[ambervdberg]

Current behavior:

When a fixture.json ONLY contains a number or a boolean, cypress throws the following error:

CypressError: TypeError: First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.
    at Function.Buffer.from (buffer.js:202:9)
    at Object.<anonymous> 

Desired behavior:

For Cypress to accept fixtures that contain a number or a boolean only.

Steps to reproduce: (app code and test code)

Fixtures:

content of my-number.json:

26

content of my-bool.json:

true

Tests:

 // fails:
    it('accepts a number', () => {
        cy.server();
        cy.route({method: 'GET', url: '/getnumber', response: 'fixture:my-number.json'}).as('mynumber');
        cy.visit('/');
        cy.wait('@mynumber').its('responseBody').should('be', 26);
    });

    // fails:
    it('accepts a boolean', () => {
        cy.server();
        cy.route({method: 'GET', url: '/getbool', response: 'fixture:my-bool.json'}).as('mybool');
        cy.visit('/');
        cy.wait('@mybool').its('responseBody').should('be', true);
    });

repo: https://github.com/amberjs/cypress-test-tiny

Versions

Cypress 3.2.0 - 3.4.1
Chrome

[ambervdberg]

Any update on this?

[jennifer-shehane]

I can verify this behavior. This is a bug. This error only occurs when you use the fixtures: shorthand within the cy.route() property.

num.json

26

spec.js

it('accepts a number in cy.fixture', () => {
  cy.server()
  cy.fixture('num.json').as('number')
  cy.visit('https://example.cypress.io/commands/files')
  cy.route('GET', 'comments/*', '@number').as('getNumber')
  cy.get('.fixture-btn').click()

  cy.wait('@getNumber').its('responseBody')
    .should('eq', 26) // passes
});

it('fails when a number in fixture:', () => {
  cy.server()
  cy.visit('https://example.cypress.io/commands/files')
  cy.route('GET', 'comments/*', 'fixture:num.json').as('getNumber')
  cy.get('.fixture-btn').click() // fails after click

  cy.wait('@getNumber').its('responseBody')
    .should('eq', 26)
});

This error used to look slightly different: in 3.0.0 for example.

Cause / Fix

This is being thrown from this line of code:

https://github.com/cypress-io/cypress/blob/issue-2869-config-changes/packages/server/lib/controllers/xhrs.coffee#L58:L58

Buffer.from only accepts a String when encoding is passed as explained here: https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_string_encoding

@sainthkh added a fix for if the JSON file is null, but this does not handle cases where the JSON file is valid and a non-string (like being a Number of Boolean). #5562

Workaround

Switch to using cy.fixture() syntax with .as() alias as shown above.

[mrmodise]

PR on the way @jennifer-shehane

[cypress-bot]

The code for this is done in cypress-io/cypress#9107, but has yet to be released.
We'll update this issue and reference the changelog when it's released.

[cypress-bot]

Released in 5.6.0.

This comment thread has been locked. If you are still experiencing this issue after upgrading to
Cypress v5.6.0, please open a new issue.