sbt task testOnly does not work Follow

I would like to run just one test using the command "testOnly". However, when I configure a SBT Task in Intellij IDEA like below:

This executes all the tests and prints the following message at the end:

[info] Passed: Total 19, Failed 0, Errors 0, Passed 19
[success] Total time: 58 s, completed 10-mar-2016 11:53:36
[error] Expected ID character
[error] Not a valid command: controllers
[error] Expected project ID
[error] Expected configuration
[error] Expected ':' (if selecting a configuration)
[error] Expected key
[error] Not a valid key: controllers (similar: console, otherResolvers, boot-resolvers)
[error] controllers.foo.FooTest
[error]                ^
Disconnected from the target VM, address: '127.0.0.1:53306', transport: 'socket'

Some questions:

• How can I execute only an specific test?
• How can I debug that specific test?

Thanks in advance!