scala - Cannot Resolve Symbol "Scalatest" -

i trying use scalatest, intellij cannot recognize:

import org.scalatest._ 

here build.sbt file, located in same directory scalatest.jar file.

scalaversion := "2.11.2"  librarydependencies += "org.scalatest" % "scalatest_2.11" % "2.2.4" % "test" 

thanks

so have convention 2 source folders:

src/main/scala/... src/test/scala/... 

the first shown blue, second green in intellij idea. library dependencies in sbt associated either of these, so

"org.foo" % "bar_2.11" % "1.2.3" 

is main dependency, available main sources (and test, because test depends on main). and

"org.foo" % "bar_2.11" % "1.2.3" % "test" 

is test dependency, available test sources. idea these libraries not required product, run unit tests.

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in example, scala-test available test sources, trying import main sources fail.