Unable to use ScalaTest

import org.scalatest.FunSuite

class MyTestSuite extends FunSuite {

}

I got the following message in Intellij IDE:

class MyTestSuite must be either declared abstract or implement abstract member '$bang$eq$eq(right: T): TripleEqualsInvocation' in 'org.scalactic.TripleEqualsSupport'

However, according to ScalaTest, there is no need to implement anything. Please advice, thanks

How do I run ScalaTest in IntelliJ?

Open the test in the editor, press Ctrl+Shift+F10 or right-click on the test class and from the context menu select Run 'test name'. IntelliJ IDEA creates a run/debug configuration for the test automatically, but if you want to edit settings in your configuration, click Run | Edit Configurations on the main menu.

I was experiencing the same problem and invalidating the caches/restarting IntelliJ fixed it.