1 files changed, 25 insertions, 0 deletions
diff --git a/test/test/DottyTest.scala b/test/test/DottyTest.scala
index f2d3ef92e..07b29a5f0 100644
--- a/test/test/DottyTest.scala
+++ b/test/test/DottyTest.scala
@@ -8,6 +8,11 @@ import Types._, Symbols._, Decorators._
 import dotty.tools.dotc.printing.Texts._
 import dotty.tools.dotc.reporting.ConsoleReporter
 import dotty.tools.dotc.core.Decorators._
+import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.Compiler
+
+import dotty.tools.dotc
+import dotty.tools.dotc.core.Phases.Phase
 
 class DottyTest {
 
@@ -33,6 +38,26 @@ class DottyTest {
     ctx
   }
 
+  def checkCompile(checkAfterPhase: String, source:String)(assertion:tpd.Tree =>Unit): Unit = {
+    val c = new Compiler {
+      override def phases = {
+        val allPhases = super.phases
+        val targetPhase = allPhases.find{p=> p.name == checkAfterPhase}
+        assert(targetPhase isDefined)
+        val phasesBefore = allPhases.takeWhile(x=> ! (x eq targetPhase.get))
+
+        val checker = new Phase{
+          def name = "assertionChecker"
+          override def run(implicit ctx: Context): Unit = assertion(ctx.compilationUnit.tpdTree)
+        }
+        phasesBefore:::List(targetPhase.get, checker)
+      }
+    }
+    c.rootContext(ctx)
+    val run = c.newRun
+    run.compile(source)
+  }
+
   def methType(names: String*)(paramTypes: Type*)(resultType: Type = defn.UnitType) =
     MethodType(names.toList map (_.toTermName), paramTypes.toList, resultType)
 }