Starting with Cypress version 12 Test Isolation was introduced. This now means the Mocha context (aka this
) is completely cleaned between tests.
Mocha context
It used to be (undocumented) that the Mocha context could be used to preserve variables across tests, for example
before(function () {
cy.fixture("example.json").as('testdata') // preserved on "this"
})
it("check testdata 1", function () {
expect(this.testdata).to.not.be.undefined // passes
})
it("check testdata 2", function () {
expect(this.testdata).to.not.be.undefined // fails in Cypress v12
})
but now that does not work.
The use of Mocha context is a bit arbitrary anyway, and requires explicit use of function-style functions which is easy to forget, particularly in places like array method callbacks Array.forEach(() => {})
.
You can still use the Cypress context to store data
before(function () {
cy.fixture("example").then(function (testdata) {
Cypress.testdata = testdata;
})
})
it("check testdata 1", function () {
expect(Cypress.testdata).to.not.be.undefined // passes
})
it("check testdata 2", function () {
expect(Cypress.testdata).to.not.be.undefined // passes
})
Note this is also undocumented and may change in the future.
Caching methods
Technically, the way to do this is to set the alias with beforeEach()
.
The cy.fixture()
command caches it's value, so you do not get the read overhead for each test (see Fixture returns outdated/false data #4716)
There is also cy.session()
for more complicated scenarios, which would be officially supported.
beforeEach(() => {
cy.session('testdata', () => {
cy.fixture("example").then(testdata => {
sessionStorage.setItem("testdata", testdata)
})
})
})
it("check testdata 1", function () {
expect(sessionStorage.getItem("testdata")).to.not.be.undefined
})
it("check testdata 2", function () {
expect(sessionStorage.getItem("testdata")).to.not.be.undefined
})
Lastly, cypress-data-session which fills a gap
From the docs
Feature |
cy.session |
cy.dataSession |
Command is |
official ✅ |
community |
Can cache |
the browser session state |
anything |
Stability |
experimental !!! not in v12 |
production |
Cache across specs |
yes |
yes |
Access to the cached data |
no ??? |
yes |
Custom validation |
no |
yes |
Custom restore |
no |
yes |
Dependent caching |
no |
yes |
Static utility methods |
limited |
all |
GUI integration |
yes |
no |
Should you use it? |
maybe |
yes |
Cypress version support |
newer versions |
all |
Cypress.env()
This is another way that is officially supported,
before(() => {
cy.fixture("example").then(testdata => {
Cypress.env("testdata", testdata)
})
})
it("log my fixture 1", function () {
expect(Cypress.env("testdata")).to.not.be.undefined // passes
})
it("log my fixture 2", function () {
expect(Cypress.env("testdata")).to.not.be.undefined // passes
})
but there are still certain tests scenarios that reset the browser completely where this may not work.