sbt assembly with Junit test fail - scala

Question

I am very new to scala and sbt.
I wanted to run Junit tests with sbt assembly.
I designed all my test an all run correctly with IntelliJ.
When i try to build with tests, it always fails giving lots of errors.
Here is my build.sbt
name := "updater"
version := "0.1-SNAPSHOT"
scalaVersion := "2.11.12"
val sparkVersion = "2.4.0"
libraryDependencies ++= Seq(
//"org.scala-lang" % "scala-reflect" % "2.11.12",
"org.apache.spark" %% "spark-core" % sparkVersion % Provided,
"org.apache.spark" %% "spark-sql" % sparkVersion % Provided,
"com.typesafe" % "config" % "1.3.4",
//Testing
"junit" % "junit" % "4.10" % Test,
"com.novocode" % "junit-interface" % "0.11" % Test
// exclude("junit", "junit-dep")
,
//"org.scalatest" %% "scalatest" % "3.0.7" % Test,
"org.easymock" % "easymock" % "4.0.2" % Test,
//Logging
"ch.qos.logback" % "logback-classic" % "1.2.3",
"com.typesafe.scala-logging" %% "scala-logging" % "3.9.0"
)
assemblyMergeStrategy in assembly := {
case PathList("src/test/resources/library.properties", xs#_*) => MergeStrategy.discard
case PathList("META-INF", xs#_*) => MergeStrategy.discard
case x => MergeStrategy.first
}
I attach you the log file as the problem, to me, as a newby seems not understandable. It is driving me crazy.
This is my abstract Test class which is supposed to initialize a spark context with #BeforeClass in every test class. I only included this because I suspect it could be the cause of the failure.
Do you have any suggestions on how to solve it?
Thanks

Answer 1

I was instanciating a class like so:
abstract class SparkTest {
val spark: SparkSession = SparkTest.spark
}
object SparkTest {
var spark: SparkSession = _
#BeforeClass
def initializeSpark(): Unit = {
spark = SparkSession
.builder()
.appName("TableUpdaterTest")
.master("local")
.getOrCreate()
}
#AfterClass
def stopSpark(): Unit = {
spark.stop()
}
}
Apparently by commenting the spark.stop() everything started to work.
Anyone has an Idea on why?