Developers test their code in chunks as it is written. Error monitoring during the development cycle alerts engineers when conflicts arise and helps them identify the root cause. So, you may wonder then, in the age of DevOps and continuous delivery, is end-to-end testing still needed? Not only is it viable, but it is also essential to [validate requirements, configurations, and functionality](https://saucelabs.com/blog/the-case-for-end-to-end-testing-in-the-age-of-devops).
End-to-end testing is the process of testing software or an application as it will be used by customers or end-users from start to finish. This takes an app or website out of the development environment and approaches it as users would.
For example, the end-to-end testing of an app would begin by making sure you’re out of the production environment and not logged in to company resources before starting the app. Then, you would put it through its paces using all of its dependencies, such as database access, API calls, third-party integrations, etc.
It can be time-consuming and resource-intensive but necessary to be confident about the experience you are delivering to your users. Fortunately, much of the process can now be automated.
The first step in end-to-end testing is to identify use cases for test scenarios. Detail each step in the process and write down the expected results. This will be from the blueprint for comparing results to expectations.
Effective end-to-end testing follows this seven-step process:
Define scenarios for testing.
Develop a testing environment that aligns with scenarios.
Analyze software and hardware requirements.
Define how systems need to respond.
Define testing methods.
Design test cases.
Run tests and analyze.
End-to-end testing includes several levels, including:
In each case, you want to put the application through multiple scenarios that users may encounter. For example, in the functional testing phase, you might want to check what happens when a user updates a payment card midway through checkout or adds more items in the shopping cart.
What you’re measuring in end-to-end testing is deviations from the norm, or expected outcomes, under different scenarios.
Think about an eCommerce platform, for example. Users would browse products and add them to a shopping cart. They may do this multiple times before heading to checkout. Then they may need to log in to an account, choose a payment method, confirm shipping information, and complete a purchase.
A lot can go wrong in that process. Each step must be tested to make sure the eCommerce app performs as intended, including integrations with a third-party payment provider, coupon codes, gift cards, or merchant accounts.
End-to-end tests must be designed for each step in the customer journey, from the first contact through the completed transaction. Measurements must be taken at every step to ensure proper outcomes and flag any anomalies that need rework.
By taking measurements at each step during the end-to-end testing process, when bugs are uncovered, isolating the problem for remediation becomes much simpler. Then, a series of unit tests can be designed to ensure the bug has been eliminated before sending the entire code through the end-to-end testing process again.
Best practices for end-to-end testing will ensure a smooth and efficient system.
Prioritize: While you want to test all aspects of an app, start with the features where failure causes maximum problems, whether it’s customer experience or ensuring a failure is not impacting your revenue stream. It’s better to address those things that will significantly impact your business first.
Test common user scenarios: It may be impossible to map out every scenario and use case. Avoid exception testing and test the most common scenarios. Integration or low-level unit testing may be a better fit for edge case user scenarios.
Make tests realistic: Most people don’t just click-click-click through apps or websites. They stop and read, look at images, or pause between actions. End-to-end testing should mirror real-life interaction as much as possible.
Error monitoring, unit tests, and integration tests come first: End-to-end testing environments will encompass the whole application, which can lead to complexity. When there are multiple errors, each point of failure has to be investigated and remediated. Resolve as many errors as possible before doing end-to-end tests.
API testing: End-to-end tests can capture front-end functional failures, but when paired with API tests, developers can determine whether the failure is functional or an API call error.
Optimize the test environment: By maintaining an optimum test environment, you can more readily begin testing. This allows for minimal setup when it’s time to test and a fast way to clear data so your test environment is ready for the next test.
There are challenges in end-to-end testing, which is why developing the plan and pathways for end-to-end tests is crucial. If you miss a step or fail to define an outcome, automation may not catch the error.
For example, workflow testing needs to be run in a particular order to mirror how a user will interact with an app. Failing to document each step a user would take can lead to bad data. Creating test suites to match the workflow can be tedious and demanding especially for complex apps. It may include running hundreds or even thousands of tests.
Testing is much easier in development environments. However, you need to be able to test in client or production environments as well. In many cases, production environments may not be available for testing. You may need to install local agents and access virtual machines. And, if a system update happens during the testing process, forget it.
You can use in-house device labs or cloud environments that simulate real devices and browsers for testing.
Development teams work extremely hard to assemble complex code bases to create amazing applications. It takes an extraordinary amount of work that can be tedious and frustrating. The result, however, is an app that performs exceptionally well when released in the wild.