Scalatest - error while Bulid project

How resolved my problem, why I can’t Bulid this two scala class files?



I added in bulid.sbt

libraryDependencies ++ = Seq(

"org.scalatest" %% "scalatest" % "3.0.5" % "test"


What are using to include dependencies? SBT? Or setting up the classpath in IntelliJ directly? I would recommend setting it up as an SBT project and then import it to IntelliJ.