We will be using IntelliJ IDEA as the IDE for all of the examples and exercises from this point onwards. Eclipse can also be used with equal ease, and if that is your preference, then you can use that.
IDE gives us some advantages over writing out test and application code in a plain text editor, such as code completion, syntax checking, formatting, project management, and a visual representation of the test execution.
Note
Community edition of IntelliJ IDEA can be freely downloaded from: https://www.jetbrains.com/idea/download/.
After installation, install the Scala plugin for IntelliJ. Navigate to Configure | Plugins, from the initial IntelliJ IDEA welcome screen, which will take you to the plugins dialog box. Here, you can search for already installed plugins or search for and install new plugins. If you are using IntelliJ version 15 or higher, then the Scala plugin will already be installed. After installation, IntelliJ will ask for a restart:
Plugin management screen in IntelliJ