Add tab completion to the partest command

We can complete partest options (I've excluded some that
aren't relevant in SBT), as well as test file names.

If `--srcpath scaladoc` is included, completion of test
paths will be based on `test/scaladoc` rather than
the default `test/files`. Note that the `--srcpath` option
is currently broken via scala partest interface, this
change to scala-partest is needed to make it work:

   https://github.com/scala/scala-partest/pull/49

I've also hijacked the `--grep` option with logic
in the SBT command itself, rather than passing this
to `partest`. Just like `./bin/partest-ack`, this looks
for either test file names or regex matches within
the contents of test, check, or flag files.

I tried for some time to make the tab completion of
thousands of filenames more user friendly, but wasn't
able to get something working. Ideally, it should
only suggest to `test/files/{pos, neg, ...}` on the
first <TAB>, and then offer files on another TAB.
Files should also be offered if a full directory
has been entered. Hopefully a SBT parser guru will
step in and add some polish here.

1 files changed, 5 insertions, 1 deletions

diff --git a/build.sbt b/build.sbt
index fa1c9835fa..a752a33315 100644
--- a/build.sbt
+++ b/build.sbt
@@ -836,4 +836,8 @@ addCommandAlias("scalac",   "compiler/compile:runMain            scala.tools.nsc
 addCommandAlias("scala",    "repl-jline-embedded/compile:runMain scala.tools.nsc.MainGenericRunner -usejavacp")
 addCommandAlias("scaladoc", "scaladoc/compile:runMain            scala.tools.nsc.ScalaDoc -usejavacp")
 addCommandAlias("scalap",   "scalap/compile:runMain              scala.tools.scalap.Main -usejavacp")
-addCommandAlias("partest",  "test/it:testOnly --")
+
+// Add tab completion to partest
+commands += Command("partest")(_ => PartestUtil.partestParser((baseDirectory in ThisBuild).value, (baseDirectory in ThisBuild).value / "test")) { (state, parsed) =>
+  ("test/it:testOnly -- " + parsed):: state
+}