Add updateClassifiers SNAPSHOT srcs test.

Currently fails with:
    [info] java.lang.AssertionError: assertion failed: Bippy should contain def release = 2, contents:
    [info] package t
    [info]
    [info] object Bippy {
    [info]   def release = 1
    [info] }

Also fails with MavenResolverPlugin.. :(

sbt/src/sbt-test/dependency-management/update-classifiers-snapshot-srcs/bippy/Bippy.scala

@@ -0,0 +1,5 @@
+package t
+
+object Bippy {
+  def release = 1
+}

sbt/src/sbt-test/dependency-management/update-classifiers-snapshot-srcs/build.sbt

@@ -0,0 +1,38 @@
+def ivyHome = Def.setting((target in LocalRootProject).value / "ivy")
+def localRepo = Def.setting((target in LocalRootProject).value / "local-repo")
+
+val commonSettings = Seq[Def.Setting[_]](
+  organization := "org.example",
+  version := "1.0-SNAPSHOT",
+  scalaVersion := "2.11.7",
+  ivyPaths := new IvyPaths((baseDirectory in ThisBuild).value, Some(ivyHome.value)),
+  fullResolvers := fullResolvers.value.filterNot(_ == projectResolver.value)
+)
+
+lazy val bippy = project settings (
+  commonSettings,
+  resolvers += Resolver.file("ivy-local", file(sys.props("user.home")) / ".ivy2" / "local")(Resolver.ivyStylePatterns),
+  publishTo := Some(Resolver.file("local-repo", localRepo.value))
+)
+
+lazy val myapp = project settings (
+  commonSettings,
+  resolvers += new MavenRepository("local-repo", localRepo.value.toURL.toString) withLocalIfFile false,
+  libraryDependencies += "org.example" %% "bippy" % "1.0-SNAPSHOT"
+)
+
+InputKey[Unit]("check") := {
+  import sbt.complete.DefaultParsers._
+  val n = (token(Space) ~> token(Digit)).map(_.asDigit).parsed
+
+  val jarname = "bippy_2.11-1.0-SNAPSHOT-sources.jar"
+  val file1 = ivyHome.value / "cache" / "org.example" / "bippy_2.11" / "srcs" / jarname
+  val file2 = ivyHome.value / "maven-cache" / "org" / "example" / "bippy_2.11" / "1.0-SNAPSHOT" / jarname
+  val file = if (file1.exists()) file1 else if (file2.exists) file2 else sys error s"$jarname MIA"
+  val jar = new java.util.jar.JarFile(file)
+  val s = IO readStream jar.getInputStream(jar.getJarEntry("Bippy.scala"))
+
+  val expected = s"def release = $n"
+  assert(s contains expected, s"""Bippy should contain $expected, contents:\n$s""")
+  ()
+}

sbt/src/sbt-test/dependency-management/update-classifiers-snapshot-srcs/changes/Bippy2.scala

@@ -0,0 +1,5 @@
+package t
+
+object Bippy {
+  def release = 2
+}

sbt/src/sbt-test/dependency-management/update-classifiers-snapshot-srcs/test

@@ -0,0 +1,12 @@
+> bippy/publish
+> myapp/updateClassifiers
+
+# Sanity check before real test
+> check 1
+
+$ copy-file changes/Bippy2.scala bippy/Bippy.scala
+
+> bippy/publish
+> myapp/updateClassifiers
+
+> check 2