When forking tests serialize Event.error as well. Closes #543.

sbt/src/sbt-test/tests/t543/project/Ticket543Test.scala

@@ -0,0 +1,31 @@
+import sbt._
+import Keys._
+import Tests._
+import Defaults._
+
+object Ticket543Test extends Build {
+	val marker = new File("marker")
+	val check = TaskKey[Unit]("check", "Check non-null error has been returned.")
+
+	lazy val root = Project("root", file("."), settings = defaultSettings ++  Seq(
+		libraryDependencies += "org.scalatest" %% "scalatest" % "1.8" % "test",
+		fork := true,
+		testListeners += new TestReportListener {
+		  def testEvent(event: TestEvent) {
+				for (e <- event.detail.filter(_.result() == org.scalatools.testing.Result.Failure)) {
+					if (e.error() ne null) {
+						marker.createNewFile()
+					}
+				}
+		  }
+		  def startGroup(name: String) {}
+		  def endGroup(name: String, t: Throwable) {}
+		  def endGroup(name: String, result: TestResult.Value) {}
+		},
+		check := {
+			val exists = marker.exists
+			marker.delete()
+			if (!exists) error("Null error had been returned previously")
+		}
+	))
+}

sbt/src/sbt-test/tests/t543/src/test/scala/Test.scala

@@ -0,0 +1,8 @@
+import org.scalatest.FunSuite
+
+class SBT543 extends FunSuite {
+  class MyCustomException(message: String) extends RuntimeException(message)
+  test("throws a custom excpetion") {
+    throw new MyCustomException("this is a custom exception")
+  }
+}

sbt/src/sbt-test/tests/t543/test

@@ -0,0 +1,3 @@
+-> test
+
+> check

testing/agent/src/main/java/sbt/ForkMain.java

@@ -48,19 +48,34 @@ public class ForkMain {
 			}
 		}
 	}
+	static class ForkError extends Exception implements Serializable {
+		private String originalMessage;
+		private StackTraceElement[] originalStackTrace;
+		private ForkError cause;
+		ForkError(Throwable t) {
+			originalMessage = t.getMessage();
+			originalStackTrace = t.getStackTrace();
+			if (t.getCause() != null) cause = new ForkError(t.getCause());
+		}
+		public String getMessage() { return originalMessage; }
+		public StackTraceElement[] getStackTrace() { return originalStackTrace; }
+		public Exception getCause() { return cause; }
+	}
 	static class ForkEvent implements Event, Serializable {
 		private String testName;
 		private String description;
 		private Result result;
+		private Throwable error;
 		ForkEvent(Event e) {
 			testName = e.testName();
 			description = e.description();
 			result = e.result();
+			if (e.error() != null) error = new ForkError(e.error());
 		}
 		public String testName() { return testName; }
 		public String description() { return description; }
-		public Result result() { return result;}
-		public Throwable error() { return null; }
+		public Result result() { return result; }
+		public Throwable error() { return error; }
 	}
 	public static void main(String[] args) throws Exception {
 		Socket socket = new Socket(InetAddress.getByName(null), Integer.valueOf(args[0]));