scala - Cassandra 单元与 scala。不是 session

Question

我正在尝试使用 cassandraunit 测试 Cassandra。我从 github 粘贴了测试并翻译为 Scala，但它不起作用。

import org.junit.Rule
import org.scalatest.FunSuite
import com.datastax.driver.core.ResultSet
import org.cassandraunit.CassandraCQLUnit
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet

class CassandraTest  extends FunSuite{

  @Rule
  val cassandraCQLUnit = new CassandraCQLUnit(new ClassPathCQLDataSet("statementsWithBlankEndings.cql", "mykeyspace"))

  test("really simple transformation") {

      val session = cassandraCQLUnit.session
      val resultSet = session.execute("select * from testCQLTable  WHERE id='1690e8da-5bf8-49e8-9583-4dff8a570737'")
      println(resultSet.iterator().next().getString("value"))

    }
}


java.lang.NullPointerException was thrown.
java.lang.NullPointerException
    at CassandraTest$$anonfun$1.apply$mcV$sp(CassandraTest.scala:21)
    at CassandraTest$$anonfun$1.apply(CassandraTest.scala:18)
    at CassandraTest$$anonfun$1.apply(CassandraTest.scala:18)
    at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
    at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
    at org.scalatest.Transformer.apply(Transformer.scala:22)
    at org.scalatest.Transformer.apply(Transformer.scala:20)
    at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:186)
    at org.scalatest.TestSuite$class.withFixture(TestSuite.scala:196)
    at org.scalatest.FunSuite.withFixture(FunSuite.scala:1560)
    at org.scalatest.FunSuiteLike$class.invokeWithFixture$1(FunSuiteLike.scala:183)
    at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:196)
    at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:196)
    at org.scalatest.SuperEngine.runTestImpl(Engine.scala:289)
    at org.scalatest.FunSuiteLike$class.runTest(FunSuiteLike.scala:196)
    at org.scalatest.FunSuite.runTest(FunSuite.scala:1560)
    at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:229)
    at org.scalatest.FunSuiteLike$$anonfun$runTests$1.apply(FunSuiteLike.scala:229)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:396)
    at org.scalatest.SuperEngine$$anonfun$traverseSubNodes$1$1.apply(Engine.scala:384)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at org.scalatest.SuperEngine.traverseSubNodes$1(Engine.scala:384)
    at org.scalatest.SuperEngine.org$scalatest$SuperEngine$$runTestsInBranch(Engine.scala:379)
    at org.scalatest.SuperEngine.runTestsImpl(Engine.scala:461)
    at org.scalatest.FunSuiteLike$class.runTests(FunSuiteLike.scala:229)
    at org.scalatest.FunSuite.runTests(FunSuite.scala:1560)
    at org.scalatest.Suite$class.run(Suite.scala:1147)
    at org.scalatest.FunSuite.org$scalatest$FunSuiteLike$$super$run(FunSuite.scala:1560)
    at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:233)
    at org.scalatest.FunSuiteLike$$anonfun$run$1.apply(FunSuiteLike.scala:233)
    at org.scalatest.SuperEngine.runImpl(Engine.scala:521)
    at org.scalatest.FunSuiteLike$class.run(FunSuiteLike.scala:233)
    at org.scalatest.FunSuite.run(FunSuite.scala:1560)
    at org.scalatest.tools.SuiteRunner.run(SuiteRunner.scala:45)
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$1.apply(Runner.scala:1340)
    at org.scalatest.tools.Runner$$anonfun$doRunRunRunDaDoRunRun$1.apply(Runner.scala:1334)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at org.scalatest.tools.Runner$.doRunRunRunDaDoRunRun(Runner.scala:1334)
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1011)
    at org.scalatest.tools.Runner$$anonfun$runOptionallyWithPassFailReporter$2.apply(Runner.scala:1010)
    at org.scalatest.tools.Runner$.withClassLoaderAndDispatchReporter(Runner.scala:1500)
    at org.scalatest.tools.Runner$.runOptionallyWithPassFailReporter(Runner.scala:1010)
    at org.scalatest.tools.Runner$.run(Runner.scala:850)
    at org.scalatest.tools.Runner.run(Runner.scala)
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.runScalaTest2(ScalaTestRunner.java:138)
    at org.jetbrains.plugins.scala.testingSupport.scalaTest.ScalaTestRunner.main(ScalaTestRunner.java:28)

session 变量为空我不知道为什么。据我了解，cassandraCQLUnit 在同一虚拟机中有一个 Cassandra 服务器。还需要做点别的吗？

Answer 1

您需要启动服务器并连接。然后您可以将数据加载到:

import com.datastax.driver.core.{Cluster, Session}
import org.cassandraunit.CQLDataLoader
import org.cassandraunit.dataset.cql.ClassPathCQLDataSet
import org.cassandraunit.utils.EmbeddedCassandraServerHelper
import org.scalatest.{BeforeAndAfterAll, FunSuite}

class CassandraTest extends FunSuite
  with BeforeAndAfterAll {

  var cluster : Cluster = _
  var session : Session = _

  override def beforeAll(): Unit = {
    EmbeddedCassandraServerHelper.startEmbeddedCassandra(EmbeddedCassandraServerHelper.CASSANDRA_RNDPORT_YML_FILE)
    cluster = EmbeddedCassandraServerHelper.getCluster()
    session = cluster.connect()

    val dataLoader = new CQLDataLoader(session)
    dataLoader.load(new ClassPathCQLDataSet("statementsWithBlankEndings.cql","mykeyspace"))
  }

  test("really simple transformation") {

    val resultSet = session.execute("select * from mykeyspace.testCQLTable  WHERE id='1690e8da-5bf8-49e8-9583-4dff8a570737'")
    println(resultSet.iterator().next().getString("value"))

  }

}