Simple scalatra-test specs2 example throws Exception

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

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.

Answer 2

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.