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How does a mocking framework benefit code development, testing efficiency and product design? Let’s explore the top six reasons to use a mocking framework!

Mocking frameworks provide the essential tools to manage and write unit tests in a timely, predictive and repeatable manner. A development team can indeed create mocks manually, but the framework tools provide significant benefits that support unit testing. Mocking framework tools provide support for unit testing, increase the accuracy of testing results, and save time by managing the more tedious aspects of tracking unit test results.

In this article, we’ll cover the top six reasons why using a mocking framework benefits product design, code development and testing effectiveness.

Key Takeaways

  • Determine why using a mocking framework benefits the quality and timeliness of application code development.
  • Learn why using a mocking framework saves on developer and testing time.
  • Find out if the ability to pre-test product designs reduces rework.
  • Test early, test often and test repeatedly for all connections.
  • Learn how mocking frameworks reduce the impact of code quality variability.
  • Enable dependency isolation for increased testing effectiveness.

What Is Mocking?

“Mocking is a process used in unit testing when the unit being tested has external dependencies. The purpose of mocking is to isolate and focus on the code being tested and not on the behavior or state of external dependencies. In mocking, the dependencies are replaced by closely controlled replacements objects that simulate the behavior of the real ones.” — JustMock webpage

Mocking is very useful when there is a missing function or connection. Mocking the missing connection allows the development and testing to continue instead of stopping and waiting. It is also very useful when there are external dependencies such as database connections, APIs, messaging systems or third-party connections required for a code release but are not currently present or available.

Mocking allows developers to simulate the expected behavior of missing objects or objects that are not in your control. Mocking additionally provides the ability to track and control code execution. Mock objects can return values and report when lines of code are executed and in what order.

Advantages of Using a Mocking Framework

The mocking framework tool enables easier tracking and development using pre-defined, editable mock objects.

Mocking frameworks can perform the following functions:

  • Create mock objects and manage their lifecycle
  • Set the expected object behavior based on pre-defined settings
  • Confirm and document when methods or lines of code are called
  • Track the order in which methods are executed
  • Enable easier debugging for mocked objects
  • Generate mocking objects automatically

Mocking frameworks are third-party libraries that save developers time and boost their productivity. The saving of time comes from not having to deal with managing the lifecycle of the mock objects and supporting the whole code responsible for tracking which method when it was executed and what value that method should return. The biggest advantage is that the saved time can be invested in what matters most—improving the application.

When selecting a mocking framework, ensure the tool performs the actions the developer needs as some don’t provide a full set of functionality. Choose the mocking framework tool that fits with the developer and unit testing plan needs. The success of the unit testing effort depends heavily on the mocking framework tool used. Developers save time on both unit test development and maintenance when using a mocking framework.

Tools like Telerik JustMock enable developers to create effective and efficient unit testing scenarios for full code coverage when such is needed.

JustMock enables developers to focus solely on testing the system under test and forget about the distracting mocking details. Mock objects are created automatically in memory when the tests are run based on the simple configuration in the unit test. There are no “physical” mock objects that have to be maintained as the project changes.

Reasons To Use a Mocking Framework

So what are these top six reasons to use a mocking framework?

1. Manage Code Quality Variability

Development teams typically include a variety of skill levels and specific areas of expertise. However, when teams of developers merge code into a single release codebase, problems occur. Developers break each other’s unit test code by creating issues with the dependent objects.

Remove the dependency issues by not depending on other developers’ code. Using a mocking framework, each developer can create unit tests with isolated dependencies. In short, write your unit tests to test the code with isolated dependencies, and other developers can’t break each other’s unit tests and force rework and time spent continually troubleshooting unit test issues.

When bugs come back from testing or are found in unit test execution, it’s more efficient to find the problem and fix it when dependencies are isolated in unit test code.

2. Organized and Effective Unit Testing

Unit tests have become an expected and necessary part of the development cycle, in part due to the popularity and success of Agile, Continuous Deployment and Rapid Development methodologies. With these fast-moving, iterative business practices, the code must be under constant test to ensure the next update is ready to deploy.

This rapid application development cycle means testing must be effective and highly efficient. However, speed and quality seldom mix. This is where unit tests come in. Instead of testing the entire codebase, unit tests can focus on one object at a time, which makes finding and fixing issues a more rapid process as well.

By using a mocking framework that works with the existing unit testing method, you increase test coverage. A mocking framework can fill in some of the blanks, so your unit tests can operate without constant babysitting. When you can move on to building other unit tests, you are able to cover more of the app’s code. And, of course, more thorough testing of code and all its connectivity requirements ensures a higher quality application.

3. Object Isolation

Using a mocking framework is the only effective way to isolate code when unit testing code. Executing tests upstream requires code isolation. When testing components or objects with dependencies that aren’t yet production-ready, using mocking will enable developers to isolate the code under test from those dependencies. (Dependencies include other code in development or missing connections for APIs or databases not yet currently active.) This will allow the developers to continue with their tasks until all production code is done.

Isolating code prevents cross-contamination and provides the opportunity to test without interference from other code or unit test executions. For example, a developer codes an object that saves data to a database. Currently, the database does not exist in production or testable form. To continue development and testing, developers use the mocking framework to simulate the database responses to unit test scenarios.

In cases like this, it’s important to keep different unit tests from interfering with one another. When one unit test changes data that is needed in a second unit test, this can cause an inaccurate test failure. This is a bad practice, but there’s a simple solution: mocking. Because mocking allows for isolation of objects, this interference is no longer an issue.

4. Confirm Design Options Before Coding

Wouldn’t it be nice to confirm a product design is possible before starting to code an application? Imagine using a mocking framework to prove design feasibility first rather than having to duplicate work when the current coding tool can’t replicate the design as intended.

Rather than prototyping a visual mockup, why not create a mock of the coded design to ensure the coding tools in use can create the design as desired? The mocking framework may be used to create unit tests to ensure connectivity to databases, messaging systems and APIs among others before coding starts. No need to redesign or find a workaround design that the customer approves. If in doubt, use the mocking framework tool to try it out.

Mocking bests other development strategies by enabling the verification of both application state and behavior. The ability to test out both application state and behavior against a variety of integrated connections improves the overall quality of the application with a minimal amount of unit testing code.

5. Support TDD or Early Testing

Using test-driven development (TDD) or early testing via unit or functional testing improves application quality. The sooner testing begins on the code, the more thoroughly tested the codebase is overall. More testing doesn’t necessarily equate to a higher quality application. However, early testing or TDD ensures testing during the code development cycle. Finding defects early saves time, resource energy and costs.

Mocking frameworks enable unit testing of all connections both internal and external as well as third-party applications. Mocking during test creation for TDD enables interface and integration test executions that otherwise may not get tested before a release build when all dependent objects are production-ready or testable and accessible to larger testing efforts.

The more testing depth achieved during development, the stronger the final application code product. Agile, continuous and rapid software development methodologies depend on reliable early testing to flush out exceptions and defects well before the full application frontend and backend are ready for production.

6. Support Testing of Backend Operations

Using a mocking framework enables early and frequent testing of backend code and connectivity. Pre-testing network, API and database connectivity saves time and ensures a more reliable release. A mocking framework simplifies and enables testing interface processes before the final code and connections are available.

Granted, defects may occur when the actual object is in use but it’s less likely than if mocking was not previously used for initial testing efforts. Improve test coverage by using a mocking framework to test all connections and backend interface objects as soon as possible.


Mocking frameworks enable effective, efficient and maintainable unit testing. Code quality and development speed improves as well as test reliability and efficiency. Essentially, mocking frameworks save time and add to the overall test coverage for an application. Product designs are testable to determine if coding them is realistic before actual coding starts.

Additionally, the earlier testing is executed on application connections, backend, databases and runtime engines, the better the chance of finding and fixing defects before the release. Mocking frameworks enable developers to focus on coding rather than creating custom mocks to simulate testing when all parts of an application are not production ready. Rather than waiting around for databases, APIs, third-party integration applications and other backend systems to get production-ready, development and testing efforts remain on schedule.

Enable full code test coverage early in the development cycle by using an effective mocking framework like Telerik JustMock.

About the Author

Amy Reichert

A QA test professional with 23+ years of QA testing experience within a variety of software development teams, Amy Reichert has extensive experience in QA process development & planning, team leadership/management, and QA project management.  She has worked on multiple types of software development methodologies including waterfall, agile, scrum, kanban and customized combinations. Amy enjoys continuing to improve her software testing craft by researching and writing on a variety of related topics. In her spare time, she enjoys gardening, cat management and the outdoors.


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