I have the following build.sbt file:

version := "0.0.1"

version in Test := "0.0.1-DEBUG"

name <<= (version) apply { v:String => "demo-%s".format(v) }

and while the version seems to be right in the "test" configuration,

> show test:version
[info] 0.0.1-DEBUG

the name doesn't seem to look at the more-specific setting.

> show name
[info] demo-0.0.1
> show test:name
[info] demo-0.0.1

This is obviously a greatly-simplified example of what i'm really trying to do, but i think it illustrates the problem/misunderstanding.

EDIT (2013-07-04): What i'm really trying to do is change javaOptions in the IntegrationTest configuration (b/c we spin up a service and then run testing code against it, and i'd like the service being tested to run in a slightly sandboxed mode). Setting javaOptions in IntegrationTest is easy enough (and show it:java-options confirms), but doesn't actually get used by runner unless i go to the trouble of explicitly defining it:runner to use it:java-options. I would have expected *:runner to prefer the most-specific dependent vars.

Here's your Build.scala translated to use inConfig as suggested by @MarkHarrah:

import sbt._
import sbt.Keys._

object DemoBuild extends Build {

  val mySettings = Seq(
    name <<= version { v => "demo-%s".format(v) }
  )

  lazy val demo = Project(
    id = "demo",
    base = file("."),
    settings = Project.defaultSettings ++ Seq(
      organization := "com.demo",
      scalaVersion := "2.10.0",
      version := "0.0.1",
      version in Test <<= version { v => "%s-DEBUG".format(v) }
    ) ++ mySettings
      ++ inConfig(Test)(mySettings)
  )
}