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With Agile being so widely adopted across the globe in software development projects, the importance of Integration testing has also increased. Since different parts or modules of the software are developed individually in Agile, you can consider the work done only if everything works well together. A flaky test is never healthy for any type of testing, but it can be considered more critical when your integration tests are flaky.
Being an experienced automation testing company, we have encountered various factors that contribute to the flakiness of an integration test and are well-versed when it comes to fixing them. So in this blog, we will be explaining in detail how you can fix a flaky integration test.
How is Integration Testing Performed?
Integration testing is the process of making sure that two or more separate software modules are working together as defined by the requirements. In most organizations, the Unit/Component/Module integration will be performed by the developers. But automation testing companies that follow the Test-Driven-Development approach will be involved in the unit/integration testing too.
Types of Integration testing:
- The Big Bang Method
- Bottom-Up Method
- Hybrid Testing Method
- Incremental Method
- Stubs and Drivers
- Top-Down Approach
Causes of Flaky Integration Tests
1. Web Driver Test
2. Shared resources
3. Third party’s reliability
4. Sleep ()
5. UI test
WebDriver is a web framework that allows us to execute cross-Browser tests. This tool is used to automate web applications to verify if it is working as expected. The Selenium WebDriver allows us to choose a programming language to create test cases, in that case, flakiness might cause.
Shared data is one of the main reasons for integration tests to be flaky. It can be caused when tests are designed with incorrect assumptions about data and memory or due to unforeseen scenarios.
Integration tests could also rely more on external software or APIs in comparison to standalone tests. During such scenarios, there could be certain dependencies to which we might have limited or no access. This is yet another reason that causes a flaky integration test.
Since integration tests involve different components or modules of an app, sleep () time can contribute to the failure of many tests. Having too short of a wait time or a too long wait time can cause failures.
All your tests might be working fine until a new feature/module/code has been added to the existing build. Such new additions can cause flaky integration tests and so it is always important to check how stable the tests are once such new integrations are made.
UI Tests can turn out to be because they basically intend to run End to End testing methods and interact with the System like how real users would. Since such tests are prone to network issues or server slowness that might introduce some unexpected flakiness.
Steps to Fix Flaky Integration Tests:
- Run the Test Regularly
- Identify the Unstable tests
- Isolate the Flaky tests
- Fix Flaky tests one at a time
- Add Stable tests back to the Test Suite.
Run the Test Regularly
Running your test suite at regular intervals is the first step in fixing flaky integration tests as it will help you identify them. So make sure to rerun the tests daily or at least once a week.
The more tests we rerun, the more we will be able to understand the tests. We will be able to determine helpful data such as the time it takes for the test to be executed on average. We will even know when and how the particular test is being triggered.
Once we have such data, it will be easier to identify the anomalies when they happen.
Identify the Unstable tests
Now that we have the data to identify any deviation, we will know where to look to find unstable tests. But be sure that not all failures attribute to a flaky test as there could be real scenarios impacting the result. So the first step would be to look into the error logs to see what has caused the failure.
But those tests might fail due to many reasons such as latency issues, network issues, environmental issues, coordination problems, and so on. So make sure to analyze why similar tests pass and fail randomly. If you dive deep and analyze the internal workings, you’ll be able to identify flaky test patterns.
Isolate the Flaky tests
A single flaky test can disrupt the integrity of your entire test suite. So the best course of action would be to isolate the flaky integration test from your test suite. Find out if removing the particular integration test will have any impact on your test suite on the whole and adapt accordingly.
Fix Flaky tests one at a time
In order to fix a flaky integration test, you must first identify the root cause of the problem, You can rerun the same test multiple times using the same code and try to identify the root cause of the flakiness. But this might turn out to be a tedious process if the tests end up failing continuously. So make sure to follow these steps
- Review the existing wait/ sleep time delay of the existing threads and make needful changes.
- Reorder the data source while running a test and have the process draw data from a different source. Though reordering the source station can help, it requires careful execution.
- Identify if any dependencies on external sources are causing flaky integration tests. It will be helpful if you simplify multiple threads to create a simple form as failures can be fixed when we have full access to our program instead of relying on external venues.
- Use mock testing to focus on the code more than the behaviors or the dependencies of the feature.
By posting comments to some of the code, adding print and wait-for statements as necessary, setting breakpoints, and closely watching the logs, you will be able to debug the problem’s root cause and resolve it.
Tip: A common trap that most testers fall into is wanting to find & fix all the flaky tests all at once. It will only cause them to take more time as it will be very hard to identify the root cause and come up with a permanent solution.
So focus on one flaky test at a time.
Add Stable tests back to the Test Suite
Once you are certain that the flakiness has been eliminated, you can add the isolated test back to your test suite. But you’ll have to rerun the tests over and over again to determine if the results you are getting are consistent. The reruns don’t end there as you’ll have to rerun your entire test suite after adding the fixed tests to make sure nothing else breaks.
Best Way to Handle Flaky Tests
One of the best ways to handle flaky tests is to prevent them. So when you write your automation scripts, make sure the tests are not dependent on one another. If there is too much dependency, you’ll not be able to evaluate the failures without looking into the application’s code. The objective of our tester should be able to write automation scripts in a way that you can execute them in any random order you want without any impact. But if there are such issues, you should consider splitting up those tests.
Flaky integration tests or flaky tests in general are very common when it comes to automation testing. But as a leading test automation service provider, we take the necessary steps to ensure that we don’t create flaky tests in the first place. Though it is not possible to completely avoid it, the overall flakiness can be considerably lowered. So even if we do face flakiness, the above-mentioned steps have always helped fix those issues and keep our test suites healthy.