Simple scalatra-test specs2 example throws Exception - scala

Question

I'm getting this exception when running the scalatra specs2 example from the scalatra docs:
ThrowableException: org.eclipse.jetty.http.HttpGenerator.flushBuffer()I (FutureTask.java:138)
Here is the test code (starting on line 5, skipping imports):
class MyAppTest extends MutableScalatraSpec {
addServlet(classOf[MyApp], "/*")
"GET / on AdminApp" should {
"return status 200" in {
get("/") {
status must_== 200
}
}
}
}
Here is the app definition:
class MyApp extends ScalatraServlet {
get("/") {
"aloha"
}
}
I'm using scalatra-specs2 2.0.4 and scala 2.9.1. I'm running an embedded jetty server using xsbt-web-plugin 0.2.10 with sbt 0.11.2. The test was executed using sbt test.
Here is the full trace:
[info] GET / on AdminApp should
[error] ! Fragment evaluation error
[error] ThrowableException: org.eclipse.jetty.http.HttpGenerator.flushBuffer()I (FutureTask.java:138)
[error] org.eclipse.jetty.testing.HttpTester.generate(HttpTester.java:225)
[error] org.scalatra.test.ScalatraTests$class.submit(ScalatraTests.scala:46)
[error] com.example.MyAppTest.submit(MyAppTest.scala:5)
[error] org.scalatra.test.ScalatraTests$class.submit(ScalatraTests.scala:71)
[error] com.example.MyAppTest.submit(MyAppTest.scala:5)
[error] org.scalatra.test.ScalatraTests$class.get(ScalatraTests.scala:127)
[error] com.example.MyAppTest.get(MyAppTest.scala:5)
[error] com.example.MyAppTest$$anonfun$1$$anonfun$apply$3.apply(MyAppTest.scala:10)
[error] com.example.MyAppTest$$anonfun$1$$anonfun$apply$3.apply(MyAppTest.scala:10)
[error] org.eclipse.jetty.http.HttpGenerator.flushBuffer()I
[error] org.eclipse.jetty.testing.HttpTester.generate(HttpTester.java:225)
[error] org.scalatra.test.ScalatraTests$class.submit(ScalatraTests.scala:46)
[error] com.example.MyAppTest.submit(MyAppTest.scala:5)
[error] org.scalatra.test.ScalatraTests$class.submit(ScalatraTests.scala:71)
[error] com.example.MyAppTest.submit(MyAppTest.scala:5)
[error] org.scalatra.test.ScalatraTests$class.get(ScalatraTests.scala:127)
[error] com.example.MyAppTest.get(MyAppTest.scala:5)
[error] com.example.MyAppTest$$anonfun$1$$anonfun$apply$3.apply(MyAppTest.scala:10)
[error] com.example.MyAppTest$$anonfun$1$$anonfun$apply$3.apply(MyAppTest.scala:10)
This is the only search result that has turned up so far:
Fragment Evaluation Error.
Can someone point me in the right direction?
Thanks,
-f

Answer 1

Still unsure of the root cause, but the test executes successfully after rolling jetty-webapp back from 8.0.3.v20111011 to 7.6.0.v20120127.

Answer 2

You probably have a conflict in your dependencies, more specifically with the Jetty library version. Since the "flush" method on HttpGenerator has changed between Jetty 6 and Jetty 7, you might be getting a "NoSuchMethodFoundError" which explains the strange "org.eclipse.jetty.http.HttpGenerator.flushBuffer()I" signature in the exception message.
This also explains why you get a "fragment evaluation error" and not a regular failure as explained in the link you mentioned.
If you give a go at the latest specs2-1.10-SNAPSHOT, you will get a better message for "fragment evaluation error" showing 'NoSuchMethodError' when that happens. This will help you diagnosing the issue faster.