Whitepaper: Top 5 Unit Testing Best Practices

Unit testing is important, but you have to do it correctly. With the right best practices, your software team can ensure quality is built into your software.

Find out the top 5 unit testing best practices to build quality into your software.


Download the whitepaper to learn about how to reap the full benefits of unit testing.

You’ll learn how to:
  • Create actionable tests for the present and future.
  • Ensure unit testing is adopted across the team.
  • Help the team avoid unit testing pitfalls.
  • Software developers employ unit testing to individually scrutinize very small parts of an application (units) to test if they’re operating properly.
  • Reaping the benefits of unit testing requires upfront time and effort, but it also saves time and effort over the life of the application.
  • In many organizations, the need to finish a project on time and budget outweighs the argument for dedicating resources to unit testing upfront. This approach is risky because it assumes defects found in QA or the field are acceptable.
  • In the long run organizations benefit from dedicating a small amount of extra time during the coding stage as opposed to excessive extra time in the integration phase.
  1. Design tests for precision.
  2. Stop writing tests from the hip.
  3. Learn the art of the assertion.
  4. Automate regular test execution.
  5. Adopt a unit testing policy.

Let’s take a closer look at each.

  1. Design tests for precision.

Don’t fall victim to the temptation to run unit tests without planning how they’ll target code and scale as it evolves. Tests require strategy to be effective – otherwise you may see a large amount of noise or tests that fail to flag defective code.

Pro tip: Avoid tests that produce a failure if a unit that isn’t the target of the test fails. For instance, if the function you’re testing depends on a different function, you’ll need to write a separate test targeting the dependent function.

  1. Stop writing tests from the hip.

Unit tests become noisier as code evolves: a key reason for failing to run them consistently and a sign that tests haven’t been maintained.

Ignoring or sporadically maintaining unit test suites is justified by arguing that rewriting the tests will put the team behind schedule. This is symptomatic of a “temporary-test” mindset in which the developer subscribes to the I-just-need-to-test-this-one-thing-right-now approach. In this case, the developer is more likely to write unit tests that can’t be maintained.

Developers must do adequate planning and maintenance in order to make sure their tests update as software evolves.

Pro tip: Don’t forget the data. Data used in test assertions can affect maintainability. Unit tests are tightly coupled to code, which helps you control data because expectations are defined alongside the test. At the same time, the cost of having the data available means that you must keep data up to date.

  1. Learn the art of assertion.

Writing assertions is very easy, which is why the number of assertions increases as the test suites grow. When you start writing test suites, it’s easy to assert everything and throw it into the code.

Pro tip: Consider where the assertions are going and ask the following questions:

  • Does this matter? Is it important?
  • Does it help me distinguish an actual failure?
  • Will I be able to maintain it in the long term?
  1. Automate regular test execution.

The simplest way to ensure unit tests are executed is to integrate automated testing into the development process. This way, developers never have to decide whether they should run a test. An additional benefit is that the tests will prevent integration problems.

Pro tip: Automating testing = complete integration, so remember that no humans should be required for review. Also, tests must be repeatable on supported configurations with no dependencies.

  1. Adopt a unit testing policy.

Testing best practices are technical in nature overall, but they also require human dili­gence. Developers are faced with making coding and testing decisions every day that go beyond the software and affecting the business. Safety, security, performance and reliability are all on the line.

To minimize risks, align software development activities with your business goals using policy-driven development, which ensures developers deliver software that matches expectations set by the business.

Policy-driven development must include:

Pro tip: Verify all unit tests by at least one peer. Peer reviewing isn’t a regular practice, but it provides tremendous value.

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About Parasoft

Parasoft’s software testing solutions support the entire software development process, from when the developer writes the first line of code all the way through unit and functional testing, to performance and security testing, leveraging simulated test environments along the way. Parasoft's unique analytics platform aggregates data from across all testing practices, providing insights up and down the testing pyramid to enable organizations to succeed in today's most strategic development initiatives, including Agile/DevOps, Continuous Testing, and the complexities of IoT. Parasoft’s automated software testing innovations fuel software development organizations, helping teams reduce the time, cost, and effort of delivering high-quality software to the market.