Test finishing with commands in its queue when calling method on undefined with cy async return

[jennifer-shehane]

When I write the following test case, an error throws saying that some commands were not finished:

describe('Test', function() {
  beforeEach(function() {
    return cy
  })

  it('asserts length', function() {
    cy.get('foobar').should('have.length', undefined.length)
  })
})

Cypress error:

CypressError: Oops, Cypress detected something wrong with your test code.

The test has finished but Cypress still has commands in its queue.
The 1 queued commands that have not yet run are:

- cy.get('foobar')

In every situation we've seen, this has been caused by programmer error.
Most often this indicates a race condition due to a forgotten 'return' or from commands in a previously run test bleeding into the current test.

For a much more thorough explanation including examples please review this error here:

https://on.cypress.io/command-queue-ended-early

But when I remove the beforeEach, the proper error is thrown: that it cannot read 'length' of undefined.

describe('Test', function() {
  it('asserts length', function() {
    cy.get('foobar').should('have.length', undefined.length)
  })
})

Cypress error:

TypeError: Cannot read property 'length' of undefined

[jennifer-shehane]

Can confirm this only happens in version 0.17.5 and up.