sbt 0.11.2 task dependencies [PARTIALLY SOLVED]

build.scala

import sbt._
import Keys._
/**
 *   How in the world do I make bye depend on hello?
 *   And how do I depend on a task like test?
 *   I have not been able to make this work
     goodbyeTask <<= goodbyeTask.dependsOn(helloTask) as in https://github.com/harrah/xsbt/wiki/Tasks
     no matter where I stick it!
     Halp!
 */
object Build extends Build {

  lazy val project = Project (
    "virtualusers",
    file (".")
  )

  override lazy val settings = super.settings ++ Seq( 
    helloTask,
    goodbyeTask
  )

  val hello = TaskKey[Unit]("hello", "Prints 'Hello World'") 
  val helloTask = hello := { println( "Hello World") }

  val goodbye = TaskKey[Unit]("bye", "Prints 'Good Bye, cruel world'")
  val goodbyeTask = goodbye := { println("Good Bye, cruel world") }

}

build2.scala

import sbt._
import Keys._

/**
 * So I tried this https://groups.google.com/forum/?fromgroups#!topic/simple-build-tool/v7y64K15PRU
 * and I get what you see in the next file
 */
object Build extends Build {

  lazy val project = Project (
    "virtualusers",
    file (".")
  )

  override lazy val settings = super.settings ++ Seq( 
    helloTask,
    goodbyeTask <<= goodbyeTask dependsOn (helloTask)
  )

  val hello = TaskKey[Unit]("hello", "Prints 'Hello World'") 
  val helloTask = hello := { println( "Hello World") }

  val goodbye = TaskKey[Unit]("bye", "Prints 'Good Bye, cruel world'")
  val goodbyeTask = goodbye := { println("Good Bye, cruel world") }

}

build3.scala

import sbt._
import Keys._

/**
 *  I have made progress ... now I need to hook into the "standard" tasks like compile.
 */
object Build extends Build {

  lazy val project = Project (
    "sbt-task-dependencies",
    file (".")
  )

  override lazy val settings = super.settings ++ Seq( 
    helloTask,
    goodbyeTask 
  )

  val hello     = TaskKey[Unit]("hello", "Prints 'Hello World'") 
  val helloTask = hello := { println( "Hello World") }

  val goodbye     = TaskKey[Unit]("bye", "Prints 'Good Bye, cruel world'")
  val goodbyeTask = goodbye  <<= (hello) map { h => println("goodbye") }

}

gistfile1.txt

I admit I am clueless. I've also looked at the wiki (obviously as my example is clearly ripped of there) but I can not find a full blown build.scala example.

What I want to achieve is just move some files around and then compress them with the `assembly`ed jar for distribution (bundle). That part is fine, I have a task that does that but I can't say:
when I type bundle I want to the tests to be run and then an assembly created.

Halp! :'(

output2.txt

[info] Compiling 1 Scala source to /Users/fede/Workshop/code/exploratory/sbt/taskDependencies/project/target/scala-2.9.1/sbt-0.11.2/classes...
[error] /Users/fede/Workshop/code/exploratory/sbt/taskDependencies/project/Build.scala:18: reassignment to val
[error]     goodbyeTask <<= goodbyeTask dependsOn (helloTask)
[error]                 ^
[error] one error found

build2.scala:15 
-      helloTask
+      helloTask,

@retronym, thanks.

It was metastasis (cut'n'paste) error both in the version of the code and it's output; It was late and I just did not recheck.
The gist is updated and the output is the correct too.

for some reason, the gist files are not in the order I create them. Anyway, this is mostly history now :D