Page.mouse.move() doesn't work in headless mode?

• Puppeteer version: 1.18.1
• Platform / OS version: Win64
• URLs (if applicable): -
• Node.js version: 8.11.2

What steps will reproduce the problem?

I am testing a tooltip plugin for webpages. In one of the cases the tooltip should follow the cursor/mouse moves along x-axis. My plugin tracks the mouse moves and then moves the tooltip accordingly. It works with headless: false, I see all that in action. But when I switch to headless mode it seems that moves don’t happen and the tooltip position remains the same.

        await page.goto(url);
        await page.waitForSelector(".example5 a"); // it's the element around which the tooltip will appear
        await page.hover(".example5 a");

        let initialTtPosLeft = parseFloat(await page.evaluate(() => document.querySelector(".example5 span.js-tooltiper").style.left)); // I take initial tooltip left pos.

        let link = await page.$('.example5 a'); // I take element's coords to use them to move the mouse later
        let linkPos = await page.evaluate((link) => {
            const {top, left} = link.getBoundingClientRect();
            return {top, left};
        }, link);

        await page.mouse.move(linkPos.left + 5, linkPos.top + 5); // I move the mouse over the element. +5 just to not go beyond element's limits.

        let finalTtPosLeft = parseFloat(await page.evaluate(() => document.querySelector(".example5 span.js-tooltiper").style.left)); // I take again tooltip's left pos

        assert.notEqual(initialTtPosLeft, finalTtPosLeft); // In headless mode they are equal as if mouse.move didn't happen

What is the expected result?

The mouse moves and triggers the tooltip moving.

What happens instead?

Seems that in headless mode it doesn’t happen since the tooltip position remains the same.

[haochenli]

I encounter the same problem that I simulate a drag event with page.mouse.down() and page.mouse.move() and page.mouse.up(). It’s work in {headless: false} mode but not in the {headless: true} mode… I spent the whole day and figure out that add page.setViewport({ width: xxx, height: xxx }); before simulating the mouse event will solve my problem.

[stale[bot]]

We are closing this issue. If the issue still persists in the latest version of Puppeteer, please reopen the issue and update the description. We will try our best to accomodate it!