WebdriverIO Re-run Service

This service tracks failing Mocha or Jasmine tests and Cucumber scenarios executed within the WebdriverIO test framework. It will allow failing or unstable tests or scenarios to be re-run.

NOTE: Users running WebdriverIO 7.x.x, use version 1.7.x version of this service. If you are on the latest major version of 8.x.x, use the latest 2.x.x version of this service.

Re-run vs. Retry

The retry logic built into WebdriverIO for Cucumber and Mocha/Jasmine is helpful for handling flaky steps in Cucumber and Mocha/Jasmine. Retrying in each framework has caveats:

• Cucumber: It does not take into account that some steps may not be able to be retried in the middle of a test. Running a step twice may break the rest of the Scenario or it may not be possible in the test context.
• Mocha/Jasmine: The retry logic may be applied to an individual test, however, this is still done in real-time and perhaps does not account for temporal issues or network connectivity problems.

The main distinctions of the re-run:

• Will re-run an entire individual Cucumber Scenario and not just a single step
• Enables an entire spec file to be re-run after a main test execution is complete
• May be copied and executed locally (retry cannot)
• Can still be used in conjunction with retry methods
• Does not require any code change to apply retry logic to flaky or problematic tests

It is recommended to take some time to evaluate the options available. A hybrid solution may be the best solution to provide the best real and actionable test results.

Installation

Using npm:

npm install wdio-rerun-service

or using yarn:

yarn add wdio-rerun-service

After package installation is complete, add it to services array in wdio.conf.js:

// wdio.conf.js
import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [RerunService, {
        // ...
    }]
};

Instructions on how to install WebdriverIO can be found here.

Usage

By design, this service does not automatically re-run failed tests.

After WebDriver.IO has completed execution, if failures or unstable tests/scenarios are found a file will be at rerunScriptPath or by default ./rerun.sh (see Configuration).

Conditional Re-run

Every teams re-run needs will differ execution could be based on any number of factors, this is an example of how to accomplish a conditional re-run based on # of failures.

attemptRerun.sh

Executes ./rerun.sh if less than 25 failures have been found in last execution of WebDriver.IO.

#!/usr/bin/env bash
MAX_TO_RERUN=${MAX_TO_RERUN:=25}
if [ -f "rerun.sh" ]; then
  echo "[rerun.sh] file exits, checking total failures."
  NUMBER_OF_FAILURES=$(grep "\-\-spec" -o rerun.sh | wc -l | xargs)
	if [ "$MAX_TO_RERUN" -gt "$NUMBER_OF_FAILURES" ]; then
    echo "Re-running $NUMBER_OF_FAILURES failed scenarios!"
    . ./rerun.sh
	else
    echo "Skipping re-run, expected < $MAX_TO_RERUN failures to qualify execution for re-run, got $NUMBER_OF_FAILURES failures."
	fi
else
  echo "No [rerun.sh] file exits, skipping re-run!"
fi

Bash Re-run Command

Execute in shell

. ./attemptRerun.sh

Integrate with NPM

Add task in package.json

"attempt-rerun": ". ./attemptRerun.sh"

NPM Re-run Command

Execute in shell

npm run attempt-rerun

Configuration

The following options may be added to the wdio.conf.js file. To define options for the service you need to add the service to the services list in the following way:

// wdio.conf.js
import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            // Re-run service options here...
        }]
    ],
    // ...
};

rerunDataDir

Directory where all the re-run JSON data will be kept during execution.

Type: String

Default: ./results/rerun

Example:

import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            rerunDataDir: './custom-rerun-directory'
        }]
    ],
    // ...
}

rerunScriptPath

Path to write re-run Bash script.

Type: String

Default: ./rerun.sh

Example:

import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            rerunScriptPath: './custom-path-for-rerun.sh'
        }]
    ],
    // ...
}

ignoredTags

(Cucumber-only) Set of Cucumber tags to exclude. If scenario contains a tag, the re-run service will skip analysis.

Type: Array

Default: []

Example:

import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            ignoredTags: ['@known_bug']
        }]
    ],
    // ...
}

commandPrefix

Prefix which will be added to the re-run command that is generated.

Type: String

Default: ''

Example:

import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            commandPrefix: "VARIABLE=true"
        }]
    ],
    // ...
}

customParameters

Parameters which will be added to the re-run command that is generated. Can be used with commandPrefix.

Type: String

Default: ''

Example:

import RerunService from 'wdio-rerun-service';
export const config = {
    // ...
    services: [
        [RerunService, {
            customParameters: "--foobar"
        }]
    ],
    // ...
}