Avoid hardcoded "2.10" in tests.

This allows us to cross build against 2.10.x and 2.11.x.

Author: retronym

src/test/scala/scala/async/TreeInterrogation.scala

@@ -15,7 +15,7 @@ class TreeInterrogation {
   @Test
   def `a minimal set of vals are lifted to vars`() {
     val cm = reflect.runtime.currentMirror
-    val tb = mkToolbox("-cp target/scala-2.10/classes")
+    val tb = mkToolbox(s"-cp ${toolboxClasspath}")
     val tree = tb.parse(
       """| import _root_.scala.async.AsyncId._
         | async {
@@ -52,7 +52,7 @@ class TreeInterrogation {
               && !dd.symbol.asTerm.isAccessor && !dd.symbol.asTerm.isSetter => dd.name
         }
     }.flatten
-    defDefs.map(_.decoded.trim).toSet mustBe (Set("foo$1", "apply", "resume$async", "<init>"))
+    defDefs.map(_.decoded.trim).toSet mustBe (Set("foo$1", "apply", "resume", "<init>"))
   }
 }
 
@@ -68,7 +68,7 @@ object TreeInterrogation extends App {
 
   withDebug {
     val cm = reflect.runtime.currentMirror
-    val tb = mkToolbox("-cp target/scala-2.10/classes -Xprint:flatten")
+    val tb = mkToolbox("-cp ${toolboxClasspath} -Xprint:flatten")
     import scala.async.Async._
     val tree = tb.parse(
       """ import _root_.scala.async.AsyncId.{async, await}

src/test/scala/scala/async/package.scala

@@ -42,7 +42,22 @@ package object async {
     m.mkToolBox(options = compileOptions)
   }
 
-  def expectError(errorSnippet: String, compileOptions: String = "", baseCompileOptions: String = "-cp target/scala-2.10/classes")(code: String) {
+  def scalaBinaryVersion: String = {
+    val Pattern = """(\d+\.\d+)\..*""".r
+    scala.util.Properties.versionNumberString match {
+      case Pattern(v) => v
+      case _          => ""
+    }
+  }
+
+  def toolboxClasspath = {
+    val f = new java.io.File(s"target/scala-${scalaBinaryVersion}/classes")
+    if (!f.exists) sys.error(s"output directory ${f.getAbsolutePath} does not exist.")
+    f.getAbsolutePath
+  }
+
+  def expectError(errorSnippet: String, compileOptions: String = "",
+                  baseCompileOptions: String = s"-cp ${toolboxClasspath}")(code: String) {
     intercept[ToolBoxError] {
       eval(code, compileOptions + " " + baseCompileOptions)
     }.getMessage mustContain errorSnippet