Merge pull request #75 from ucb-bar/meaningfulerror

Meaningful error when resource copy fails.
Seems like this is exposing some deeper error with sbt and external libraries/jars.  Sometimes this error message makes sometimes the entire JVM and sbt dump with SEG fault, I don't think this is a chisel problem

1 files changed, 4 insertions, 1 deletions

diff --git a/src/main/scala/Chisel/testers/TesterDriver.scala b/src/main/scala/Chisel/testers/TesterDriver.scala
index 4da5d059..b25b160b 100644
--- a/src/main/scala/Chisel/testers/TesterDriver.scala
+++ b/src/main/scala/Chisel/testers/TesterDriver.scala
@@ -11,13 +11,16 @@ object TesterDriver extends BackendCompilationUtilities {
     */
   def copyResourceToFile(name: String, file: File) {
     val in = getClass().getResourceAsStream(name)
+    if (in == null) {
+      throw new FileNotFoundException(s"Resource '$name'")
+    }
     val out = new FileOutputStream(file)
     Iterator.continually(in.read).takeWhile(-1 !=).foreach(out.write)
     out.close()
   }
 
   /** For use with modules that should successfully be elaborated by the
-    * frontend, and which can be turned into executeables with assertions. */
+    * frontend, and which can be turned into executables with assertions. */
   def execute(t: () => BasicTester, additionalVResources: Seq[String] = Seq()): Boolean = {
     // Invoke the chisel compiler to get the circuit's IR
     val circuit = Driver.elaborate(t)