'How to implement drag and drop in cypress test?

I am struggling to test drag and drop with Cypress and Angular Material Drag and Drop. So the goal is to move "Get to work" from Todo to Done. I have created the following test, that should make it easy for you to reproduce:

You can play with the Stackblitz here.

describe('Trying to implement drag-n-drop', () => {

    before(() => {
        Cypress.config('baseUrl', null);

        cy.viewport(1000, 600);
        cy.visit('https://angular-oxkc7l-zirwfs.stackblitz.io')
        .url().should('contain', 'angular')
        .get('h2').should('contain', 'To do');
    });

    it('Should work, based on this https://stackoverflow.com/a/54119137/3694288', () => {

        const dataTransfer = new DataTransfer;

        cy.get('#cdk-drop-list-0 > :nth-child(1)')
            .trigger('dragstart', { dataTransfer });

        cy.get('#cdk-drop-list-1')
            .trigger('drop', { dataTransfer });

        cy.get('#cdk-drop-list-0 > :nth-child(1)')
            .trigger('dragend');

        cy.get('#cdk-drop-list-1').should('contain', 'Get to work');
    });


    it('Should work, with this library https://github.com/4teamwork/cypress-drag-drop', () => {
        cy.get('#cdk-drop-list-0 > :nth-child(1)')
            .drag('#cdk-drop-list-1');

        cy.get('#cdk-drop-list-1').should('contain', 'Get to work');
    });

});

The result from running the above test, looks like this:

enter image description here

Here is a repo to develop a solution.

Thanks for the help.

Events fired, found using the chrome debugger:

Item

  • pointerover
  • pointerenter
  • mouseover
  • mousedown
  • pointermove
  • mousemove
  • pointerout
  • pointerleave
  • mouseout
  • mouseleave

Drop zone

  • pointerover
  • pointerenter
  • mouseover
  • pointermove
  • mousemove
  • pointerleave
  • mouseout
  • mouseleave

Solution

After @Richard Matsen's awesome answer I ended up with adding his answer as a custom command. The solution looks like this

support/drag-support.ts

    export function drag(dragSelector: string, dropSelector: string) {
        // Based on this answer: https://stackoverflow.com/a/55436989/3694288
        cy.get(dragSelector).should('exist')
          .get(dropSelector).should('exist');
    
          const draggable = Cypress.$(dragSelector)[0]; // Pick up this
          const droppable = Cypress.$(dropSelector)[0]; // Drop over this
    
          const coords = droppable.getBoundingClientRect();
          draggable.dispatchEvent(<any>new MouseEvent('mousedown'));
          draggable.dispatchEvent(<any>new MouseEvent('mousemove', {clientX: 10, clientY: 0}));
          draggable.dispatchEvent(<any>new MouseEvent('mousemove', {
              // I had to add (as any here --> maybe this can help solve the issue??)
              clientX: coords.left + 10,
              clientY: coords.top + 10  // A few extra pixels to get the ordering right
          }));
          draggable.dispatchEvent(new MouseEvent('mouseup'));
          return cy.get(dropSelector);
    }

support/commands.ts

    // Add typings for the custom command
    declare global {
        namespace Cypress {
            interface Chainable {
                drag: (dragSelector: string, dropSelector: string) => Chainable;
            }
        }
    }
    // Finally add the custom command
    Cypress.Commands.add('drag', drag);

in the spec file

    it('🔥 Thx to Stackoverflow, drag and drop support now works 🔥', () => {
       cy.drag('#cdk-drop-list-0 > :nth-child(1)', '#cdk-drop-list-1')
       .should('contain', 'Get to work');
    });

A small giph, because I'm just so happy it finally works 😲

enter image description here

CI

Now it also works in CI 🔥 (and electron locally). Tested with CircleCI 2.0.

angularcypressangular-material2


Solution 1:[1]

Dispatching MouseEvents seems to be the only way to test Angular Material drag and drop.

You should also be aware of the following issue, which tests in Protractor but also applies to this Cypress test

CDK DragDrop Regression between 7.0.0-beta.2 and 7.0.0-rc.2: Protractor tests stopped working #13642,

It seems that (for want of a better explanation) an additional nudge is needed on the mousemove.

The steps given as a workaround (Protractor syntax),

private async dragAndDrop ( $element, $destination ) {
  await browser.actions().mouseMove( $element ).perform();
  await browser.actions().mouseDown( $element ).perform();
  await browser.actions().mouseMove( {x: 10, y: 0 } ).perform();
  await browser.actions().mouseMove( $destination ).perform();
  return browser.actions().mouseUp().perform();
}

can be translated into a Cypress test, the simplest form I found is

it('works (simply)', () => {
  const draggable = Cypress.$('#cdk-drop-list-0 > :nth-child(1)')[0]  // Pick up this
  const droppable = Cypress.$('#cdk-drop-list-1 > :nth-child(4)')[0]  // Drop over this

  const coords = droppable.getBoundingClientRect()
  draggable.dispatchEvent(new MouseEvent('mousedown'));
  draggable.dispatchEvent(new MouseEvent('mousemove', {clientX: 10, clientY: 0}));
  draggable.dispatchEvent(new MouseEvent('mousemove', {
    clientX: coords.x+10,   
    clientY: coords.y+10  // A few extra pixels to get the ordering right
  }));
  draggable.dispatchEvent(new MouseEvent('mouseup'));

  cy.get('#cdk-drop-list-1').should('contain', 'Get to work');
  cy.get('#cdk-drop-list-1 > .cdk-drag').eq(3).should('contain', 'Get to work');

});

Notes

  • The problem in the referenced issue is not limited to Protractor. If you remove the first mousemove in the Cypress test, it also fails.
  • The cy.get(..).trigger() syntax does not seem to work with Angular, but native dispatchEvent() does.
  • Dragging over a specific element in the target list (as opposed to just dropping on the list) gives precise positioning within the target list.
  • dragstart, dragend may not be appropriate for Angular Material, as the code shows the event received is type CdkDragDrop rather than a DataTransfer object.
  • If content is asynchronously fetched, you may have to switch from Cypress.$(...) to cy.get(...).then(el => {...}), to take advantage of cypress' auto retry in commands.
  • I had to add a 10 second timeout to visit the Stackblitz url.

Async list fetching

If the list is fetched by an async Angular service (httpClient) during component construction, using this in the test 

const draggable = Cypress.$('#cdk-drop-list-0 > :nth-child(1)')[0]

will not work, because the nth-child will not be present immediately, only after the fetch completes.

Instead, you can use cy.get() to provide retries up to a timeout (default 5 seconds).

cy.get('#cdk-drop-list-0 > :nth-child(1)').then(el => {
  const draggable = el[0]  // Pick up this
  cy.get('#cdk-drop-list-1 > :nth-child(4)').then(el => {
    const droppable = el[0]  // Drop over this

    const coords = droppable.getBoundingClientRect()
    draggable.dispatchEvent(new MouseEvent('mousemove'));
    draggable.dispatchEvent(new MouseEvent('mousedown'));
    draggable.dispatchEvent(new MouseEvent('mousemove', {clientX: 10, clientY: 0}));
    draggable.dispatchEvent(new MouseEvent('mousemove', {clientX: coords.x+10, clientY: coords.y+10}));
    draggable.dispatchEvent(new MouseEvent('mouseup'));

  })

  cy.get('#cdk-drop-list-1').should('contain', 'Get to work');
  cy.get('#cdk-drop-list-1 > .cdk-drag').eq(3).should('contain', 'Get to work');
})

or my preference is to use a 'canary' test to ensure loading is complete, something like

before(() => {
  cy.get('#cdk-drop-list-0 > :nth-child(1)') // Canary - wait 5s for data
})

it('should...', () => {
  const draggable = Cypress.$('#cdk-drop-list-0 > :nth-child(1)')[0]  // Pick up this
  const droppable = Cypress.$('#cdk-drop-list-1 > :nth-child(4)')[0]  // Drop over this
  ...
})

Typescript support

Warning - this is a quick hack to get over Typescript compiler problems, and could be improved.

const coords: ClientRect = droppable.getBoundingClientRect()
draggable.dispatchEvent(new (<any>MouseEvent)('mousemove'));
draggable.dispatchEvent(new (<any>MouseEvent)('mousedown'));
draggable.dispatchEvent(new (<any>MouseEvent)('mousemove', {clientX: 10.0, clientY: 0.0}));
draggable.dispatchEvent(new (<any>MouseEvent)('mousemove', {clientX: coords.left + 10.0, clientY: coords.top + 10.0}));
draggable.dispatchEvent(new (<any>MouseEvent)('mouseup'));

Solution 2:[2]

I've written up a small example for how to implement drag and drop.

It works by adding a dragTo command like so:

/// <reference types="cypress"/>

it('works', () => {
  cy.visit('https://angular-oxkc7l-zirwfs.stackblitz.io/')
  cy.contains('To do', { timeout: 15000 }) // ensure page is loaded -__-

  const item = '.example-box:not(.cdk-drag-placeholder)'

  cy.get('#cdk-drop-list-1').children(item).should('have.length', 5)

  cy.get('.example-box:contains("Get to work")').dragTo('.example-box:contains("Get up")')
  cy.get('#cdk-drop-list-1').children(item).should('have.length', 6)

  // interpolates 10 extra mousemove events on the way
  cy.get('#cdk-drop-list-0').dragTo('#cdk-drop-list-1', { steps: 10 })
  cy.get('#cdk-drop-list-1').children(item).should('have.length', 7)

  // sets steps >= 10
  cy.get('#cdk-drop-list-0').dragTo('#cdk-drop-list-1', { smooth: true })
  cy.get('#cdk-drop-list-1').children(item).should('have.length', 8)

  cy.get('#cdk-drop-list-0').dragTo('#cdk-drop-list-1')
  cy.get('#cdk-drop-list-1').children(item).should('have.length', 9)
})

To add it, try putting this in your support/index.js or pasting it at the bottom of a spec file (warning: poor code quality):


const getCoords = ($el) => {
  const domRect = $el[0].getBoundingClientRect()
  const coords = { x: domRect.left + (domRect.width / 2 || 0), y: domRect.top + (domRect.height / 2 || 0) }

  return coords
}

const dragTo = (subject, to, opts) => {

  opts = Cypress._.defaults(opts, {
    // delay inbetween steps
    delay: 0,
    // interpolation between coords
    steps: 0,
    // >=10 steps
    smooth: false,
  })

  if (opts.smooth) {
    opts.steps = Math.max(opts.steps, 10)
  }

  const win = subject[0].ownerDocument.defaultView

  const elFromCoords = (coords) => win.document.elementFromPoint(coords.x, coords.y)
  const winMouseEvent = win.MouseEvent

  const send = (type, coords, el) => {

    el = el || elFromCoords(coords)

    el.dispatchEvent(
      new winMouseEvent(type, Object.assign({}, { clientX: coords.x, clientY: coords.y }, { bubbles: true, cancelable: true }))
    )
  }

  const toSel = to

  function drag (from, to, steps = 1) {

    const fromEl = elFromCoords(from)

    const _log = Cypress.log({
      $el: fromEl,
      name: 'drag to',
      message: toSel,
    })

    _log.snapshot('before', { next: 'after', at: 0 })

    _log.set({ coords: to })

    send('mouseover', from, fromEl)
    send('mousedown', from, fromEl)

    cy.then(() => {
      return Cypress.Promise.try(() => {

        if (steps > 0) {

          const dx = (to.x - from.x) / steps
          const dy = (to.y - from.y) / steps

          return Cypress.Promise.map(Array(steps).fill(), (v, i) => {
            i = steps - 1 - i

            let _to = {
              x: from.x + dx * (i),
              y: from.y + dy * (i),
            }

            send('mousemove', _to, fromEl)

            return Cypress.Promise.delay(opts.delay)

          }, { concurrency: 1 })
        }
      })
      .then(() => {

        send('mousemove', to, fromEl)
        send('mouseover', to)
        send('mousemove', to)
        send('mouseup', to)
        _log.snapshot('after', { at: 1 }).end()

      })

    })

  }

  const $el = subject
  const fromCoords = getCoords($el)
  const toCoords = getCoords(cy.$$(to))

  drag(fromCoords, toCoords, opts.steps)
}

Cypress.Commands.addAll(
  { prevSubject: 'element' },
  {
    dragTo,
  }
)

enter image description here

Solution 3:[3]

After a lot of battling, I managed to make the drag and drop work with this:

cy.get('.list .item')
      .contains(startpos)
      .trigger('dragstart', { dataTransfer: new DataTransfer });
cy.get('.list .item')
      .eq(endpos)
      .trigger('drop')
      .trigger('dragend');

Pretty easy to use.

Solution 4:[4]

In case anyone is also struggling with cdkDropListEntered not being triggered, you might want to check if there is any scrolling going on.

Since scrolling is handled by CDK (e.g. https://github.com/angular/components/blob/master/src/cdk/scrolling/viewport-ruler.ts#L131), I had to add the scroll position to any mouse events. The scroll position is computed like this (corresponding to above link):

const win = subject[0].ownerDocument.defaultView;
const window = win;
const document = window.document;
const documentElement = document.documentElement;
const documentRect = documentElement.getBoundingClientRect();

const top =
  -documentRect.top ||
  document.body.scrollTop ||
  window.scrollY ||
  documentElement.scrollTop ||
  0;

const left =
  -documentRect.left ||
  document.body.scrollLeft ||
  window.scrollX ||
  documentElement.scrollLeft ||
  0;

where subject is the result yielded e.g. by a cy.get command.

Solution 5:[5]

You just need to replace the class or id from where you want to drag and drop

const dataTransfer = new DataTransfer(); 
cy.get('ID or class which you want to drag').trigger('dragstart',{
   dataTransfer 
  });
cy.get('ID or class where  you want to drop').trigger('drop',{
     dataTransfer
});

Solution 6:[6]

If there is not any steps involved in beween drag and drop then use below steps :

Download this for running scripts having drag and drop

npm install --save-dev @4tw/cypress-drag-drop

Go to cypress.json

"compilerOptions": {
            "types": ["cypress", "@4tw/cypress-drag-drop"]
            }

add this on cypress.json

Go on command.js

 require('@4tw/cypress-drag-drop')

USE

cy.get('Class or id which you want to drag ').drag('Class or id where you want to drop')

Solution 7:[7]

Did you take a look at the official recipe that does exactly the same?

It uses this combination of triggered events

cy.get('.selector')
  .trigger('mousedown', { which: 1 })
  .trigger('mousemove', { clientX: 400, clientY: 500 })
  .trigger('mouseup', {force: true})

to drag&drop the item, let me know if you need some more help when you have tried it ?

Solution 8:[8]

Not Angular specific, but should be generic and simple enough to tweak if needed. I did try a lot of recipes out there and also cypress-file-upload but that wouldn't work with webp for example.

The command below seems to work for most cases and reflects pretty closely what a user would do

Cypress.Commands.add('dropFile', {prevSubject: true}, (subject, fileName, fileType) => {
  return cy.fixture(fileName, 'binary').then((data) => {
    return Cypress.Blob.binaryStringToBlob(data, fileType).then(blob => {
      const file = new File([blob], fileName, {type: fileType});
      const dataTransfer = new DataTransfer();
      dataTransfer.items.add(file);
      cy.wrap(subject)
        .trigger("dragenter", {force: true})
        .trigger("drop", {dataTransfer})
    })
  })
})

Ensure fixturesFolder is specified in your cypress.json config file. Then you simply use like below

cy.get("#dropzone").dropFile("myfile1.webp", "image/webp")
cy.get("#dropzone").dropFile("myfile2.jpg", "image/jpeg")

Solution 9:[9]

Here's my cypress command for this:

Cypress.Commands.add(
  'dragTo',
  (selector: string, position: { x: number; y: number }) => {
    const log = Cypress.log({
      message: `Drag ${selector} to (${position.x}, ${position.y})`,
      consoleProps: () => ({ selector, position })
    });
    log.snapshot('before');
    const ret = cy
      .get(selector, { log: false })
      .trigger('mouseover', { force: true, log: false })
      .trigger('mousedown', {
        button: 0,
        log: false
      })
      .trigger('mousemove', {
        pageX: 10,
        pageY: 10,
        log: false
      })
      .then(el => {
        log.snapshot('Drag start');
        return el;
      })
      .trigger('mousemove', {
        pageX: position.x,
        pageY: position.y,
        force: true,
        log: false
      })
      .then(event => {
        log.snapshot('Drag End');
        return event;
      })
      .trigger('mouseup', { force: true, log: false })
      .then(() => {
        log.snapshot('after');
      });
    log.end();
    return ret;
  }
);

Solution 10:[10]

Try this:

  it('should drag and drop the element', () => {
    const myItem = cy.get('my-item').first();
    myItem.trigger('mousedown', 100, 100, { force: true }).trigger('mousemove', 300, 300, { force: true });
    myItem.click().trigger('mouseup', { force: true });
});

Solution 11:[11]

I kept having the problem with dropevent.isPointerOverContainer always being false with the other solutions here, so instead of mouseup at the end, I had to use click(). It was the only way to get the pointer position and drag position to be in the correct location to fire the drop() event in my component.

export function drag(dragSelector: string, dropSelector: string) {
  // Based on this answer: https://stackoverflow.com/questions/55361499/how-to-implement-drag-and-drop-in-cypress-test
  cy.get(dragSelector).should('exist').get(dropSelector).should('exist');

  const draggable = Cypress.$(dragSelector)[0]; // Pick up this
  const droppable = Cypress.$(dropSelector)[0]; // Drop over this
  const coords = droppable.getBoundingClientRect();

  draggable.dispatchEvent(<any>new MouseEvent('mousedown'));
  draggable.dispatchEvent(<any>new MouseEvent('mousemove', {clientX: 10, clientY: 0}));
  draggable.dispatchEvent(<any>new MouseEvent('mousemove', {clientX: coords.left + 40, clientY: coords.top + 10}));
  cy.get(dropSelector).click();
  //   draggable.dispatchEvent(new MouseEvent('mouseup'));

  return cy.get(dropSelector);
}

// Add typings for the custom command
declare global {
  namespace Cypress {
    interface Chainable {
      drag: (dragSelector: string, dropSelector: string) => Chainable;
    }
  }
}
// Finally add the custom command
Cypress.Commands.add('drag', drag);

Solution 12:[12]

For those who are struggling with Drag and Drop and "react-beautiful-dnd" library, here is a piece of code that helped me (nothing else did). It's extracted from this post

Cypress.Commands.add('dragAndDrop', (subject, target) => {
Cypress.log({
    name: 'DRAGNDROP',
    message: `Dragging element ${subject} to ${target}`,
    consoleProps: () => {
        return {
            subject: subject,
            target: target
        };
    }
});
const BUTTON_INDEX = 0;
const SLOPPY_CLICK_THRESHOLD = 10;
cy.get(target)
    .first()
    .then($target => {
        let coordsDrop = $target[0].getBoundingClientRect();
        cy.get(subject)
            .first()
            .then(subject => {
                const coordsDrag = subject[0].getBoundingClientRect();
                cy.wrap(subject)
                    .trigger('mousedown', {
                        button: BUTTON_INDEX,
                        clientX: coordsDrag.x,
                        clientY: coordsDrag.y,
                        force: true
                    })
                    .trigger('mousemove', {
                        button: BUTTON_INDEX,
                        clientX: coordsDrag.x + SLOPPY_CLICK_THRESHOLD,
                        clientY: coordsDrag.y,
                        force: true
                    });
                cy.get('body')
                    .trigger('mousemove', {
                        button: BUTTON_INDEX,
                        clientX: coordsDrop.x,
                        clientY: coordsDrop.y,
                        force: true            
                    })
                    .trigger('mouseup');
            });
    });
});

Solution 13:[13]

for me the code from @bkucera works, thanks for that. but I had to chance 3 things in order to works for me as expected:

1.

let _to = {
              x: from.x + dx * (i),
              y: from.y - dy * (i),
            }

  1. i = i+1

  2. had to use some delay, steps and smooth:true

delay: 30,
steps: 30,
smooth: true,

Solution 14:[14]

const dataTransfer = new DataTransfer();
cy.get('#your-item-id').trigger('dragstart', { dataTransfer });
cy.get('#your-dropable-div').trigger('drop', { dataTransfer });

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