Prerequisites to mock object in Scala

1. Add the ScalaMock dependency to your project:

If you’re using SBT, add the following line to your build.sbt file:

libraryDependencies += “org.scalamock” % “scalamock” % “5.1.0” % Test

This will add ScalaMock as a test dependency in your project.

2. Import required classes:

In your test suite file, you need to import the following classes:

import org.scalamock.scalatest.MockFactory
import org.scalatest.flatspec.AnyFlatSpec

• MockFactory provides utility methods to create mock objects.
• AnyFlatSpec is a trait from ScalaTest that provides the testing framework. You can use any other test suite trait from ScalaTest as per your preference.

3. Extend your test suite with MockFactory:

Your test suite class should extend AnyFlatSpec and MockFactory.

For example:

class MyServiceSpec extends AnyFlatSpec with MockFactory {
Your tests go here
}

Extending MockFactory allows you to use the mock method to create mock objects.

4. Define the trait or class you want to mock:

You need to have a trait or class that you want to mock.

For example:

scalaCopy codetrait MyService {
def doSomething(arg: String): String
}

With these prerequisites in place, you can start mocking objects in your tests using ScalaMock.

In software development, mocking is a technique used to isolate the unit under test by replacing external dependencies with simulated objects or “mocks”. Mocking is particularly useful when working with objects that are difficult to set up or have side effects, such as databases, web services, or file systems.

Scala provides several libraries for mocking objects, including ScalaMock, MockFactory, and EasyMock. In this article, we’ll focus on using ScalaMock, which is a popular and lightweight mocking library for Scala.