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Taiko Documentation

Taiko in Docker

This tutorial shows how to setup Taiko tests in Docker. The Docker image created as a part of this tutorial can be used to run tests locally or on a CI/CD setup.

The Dockerfile in this sample uses Gauge to run the tests, However, you can modify the Dockerfile to exclude it or use another test runner.

Prerequisites

Section titled “Prerequisites”

Setup a sample project

Section titled “Setup a sample project”
 gauge init js

This creates a Gauge+Taiko project sample with a Dockerfile in the current directory.

Using the Dockerfile

Section titled “Using the Dockerfile”

Building the image

Section titled “Building the image”

Run the following command from the project’s folder

docker build -t gauge-taiko .

Running tests

Section titled “Running tests”
docker run  --rm -it -v ${PWD}/reports:/gauge/reports gauge-taiko

The test reports are created in the reports folder in the current directory.

A note on the flags and options

Section titled “A note on the flags and options”

TAIKO_BROWSER_ARGS

Section titled “TAIKO_BROWSER_ARGS”

Taiko reads TAIKO_BROWSER_ARGS environment variable and passes the values as command line arguments to the Chromium browser it launches.

Note: this does not apply if the browser is launched independently and Taiko is made to connect to the already running browser instance.

---no-sandbox

Section titled “---no-sandbox”

Lighthouse-ci has documented chrome sandboxing and nuances with Docker here - —No-sandbox Issues are explained - “Chrome uses sandboxing to isolate renderer processes and restrict their capabilities. If a rogue website is able to discover a browser vulnerability and break out of JavaScript engine for example, they would find themselves in a very limited process that can’t write to the filesystem, make network requests, mess with devices, etc.”

There are several options to run Chrome headless in Docker. Puppeteer has a couple of recommendations.

According to Lighthouse-ci, passing --no-sandbox may not be a bad option. The same applies to Taiko as well. Please note that several options (other than passing --no-sandbox to chrome) require permissions/changes that apply to the entire container.

—start-maximized

Section titled “—start-maximized”

Modern websites are often built to be responsive. To ensure that the browser opens in full view-port use --start-maximized flag. Alternatively, set --window-size flag to open the website in specific viewport size.

—disable-dev-shm

Section titled “—disable-dev-shm”

By default, Docker runs a container with a /dev/shm shared memory space 64MB. This is typically too small for Chrome and will cause Chrome to crash when rendering large pages. To fix, run the container with docker run --shm-size=1gb to increase the size of /dev/shm. Since Chrome 65, this is no longer necessary. Instead, launch the browser with the --disable-dev-shm-usage flag: - Puppeteer troubleshooting tips

Project code in docker

Section titled “Project code in docker”

The project code can be made available on the Docker using various methods (besides adding it to the container at build time).

node_modules can have OS specific files which also get mounted on to the Docker. If the Docker is running for a different OS configuration, this will give errors unless node_modules is deleted before mounting.