350 lines
9.8 KiB
ReStructuredText
350 lines
9.8 KiB
ReStructuredText
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.. _multi-jvm-testing:
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###################
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Multi-JVM Testing
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###################
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Support for running applications (objects with main methods) and
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ScalaTest tests in multiple JVMs.
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.. contents:: :local:
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Setup
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=====
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The multi-JVM testing is an sbt plugin that you can find here:
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http://github.com/typesafehub/sbt-multi-jvm
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You can add it as a plugin by adding the following to your plugins/build.sbt::
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resolvers += "Typesafe Repo" at "http://repo.typesafe.com/typesafe/releases/"
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libraryDependencies += "com.typesafe.sbt-multi-jvm" %% "sbt-multi-jvm" % "0.1.3"
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You can then add multi-JVM testing to a project by including the ``MultiJvm``
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settings and config. For example, here is how the akka-cluster project adds
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multi-JVM testing::
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import MultiJvmPlugin.{ MultiJvm, extraOptions }
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lazy val cluster = Project(
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id = "akka-cluster",
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base = file("akka-cluster"),
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settings = defaultSettings ++ MultiJvmPlugin.settings ++ Seq(
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extraOptions in MultiJvm <<= (sourceDirectory in MultiJvm) { src =>
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(name: String) => (src ** (name + ".conf")).get.headOption.map("-Dakka.config=" + _.absolutePath).toSeq
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},
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test in Test <<= (test in Test) dependsOn (test in MultiJvm)
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)
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) configs (MultiJvm)
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You can specify JVM options for the forked JVMs::
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jvmOptions in MultiJvm := Seq("-Xmx256M")
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Running tests
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=============
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The multi-jvm tasks are similar to the normal tasks: ``test``, ``test-only``,
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and ``run``, but are under the ``multi-jvm`` configuration.
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So in Akka, to run all the multi-JVM tests in the akka-cluster project use (at
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the sbt prompt):
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.. code-block:: none
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akka-cluster/multi-jvm:test
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Or one can change to the ``akka-cluster`` project first, and then run the
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tests:
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.. code-block:: none
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project akka-cluster
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multi-jvm:test
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To run individual tests use ``test-only``:
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.. code-block:: none
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multi-jvm:test-only akka.cluster.deployment.Deployment
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More than one test name can be listed to run multiple specific
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tests. Tab-completion in sbt makes it easy to complete the test names.
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It's also possible to specify JVM options with ``test-only`` by including those
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options after the test names and ``--``. For example:
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.. code-block:: none
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multi-jvm:test-only akka.cluster.deployment.Deployment -- -Dsome.option=something
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Creating application tests
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==========================
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The tests are discovered, and combined, through a naming convention. A test is
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named with the following pattern:
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.. code-block:: none
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{TestName}MultiJvm{NodeName}
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That is, each test has ``MultiJvm`` in the middle of its name. The part before
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it groups together tests/applications under a single ``TestName`` that will run
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together. The part after, the ``NodeName``, is a distinguishing name for each
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forked JVM.
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So to create a 3-node test called ``Sample``, you can create three applications
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like the following::
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package sample
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object SampleMultiJvmNode1 {
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def main(args: Array[String]) {
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println("Hello from node 1")
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}
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}
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object SampleMultiJvmNode2 {
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def main(args: Array[String]) {
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println("Hello from node 2")
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}
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}
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object SampleMultiJvmNode3 {
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def main(args: Array[String]) {
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println("Hello from node 3")
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}
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}
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When you call ``multi-jvm:run sample.Sample`` at the sbt prompt, three JVMs will be
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spawned, one for each node. It will look like this:
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.. code-block:: none
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> multi-jvm:run sample.Sample
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...
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[info] Starting JVM-Node1 for sample.SampleMultiJvmNode1
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[info] Starting JVM-Node2 for sample.SampleMultiJvmNode2
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[info] Starting JVM-Node3 for sample.SampleMultiJvmNode3
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[JVM-Node1] Hello from node 1
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[JVM-Node2] Hello from node 2
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[JVM-Node3] Hello from node 3
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[success] Total time: ...
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Naming
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======
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You can change what the ``MultiJvm`` identifier is. For example, to change it to
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``ClusterTest`` use the ``multiJvmMarker`` setting::
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multiJvmMarker in MultiJvm := "ClusterTest"
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Your tests should now be named ``{TestName}ClusterTest{NodeName}``.
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Configuration of the JVM instances
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==================================
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Setting JVM options
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-------------------
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You can define specific JVM options for each of the spawned JVMs. You do that by creating
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a file named after the node in the test with suffix ``.opts`` and put them in the same
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directory as the test.
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For example, to feed the JVM options ``-Dakka.cluster.nodename=node1`` and
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``-Dakka.cluster.port=9991`` to the ``SampleMultiJvmNode1`` let's create three ``*.opts`` files
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and add the options to them.
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``SampleMultiJvmNode1.opts``::
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-Dakka.cluster.nodename=node1 -Dakka.cluster.port=9991
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``SampleMultiJvmNode2.opts``::
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-Dakka.cluster.nodename=node2 -Dakka.cluster.port=9992
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``SampleMultiJvmNode3.opts``::
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-Dakka.cluster.nodename=node3 -Dakka.cluster.port=9993
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Overriding akka.conf options
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----------------------------
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You can also override the options in the ``akka.conf`` file with different options for each
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spawned JVM. You do that by creating a file named after the node in the test with suffix
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``.conf`` and put them in the same directory as the test .
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For example, to override the configuration option ``akka.cluster.name`` let's create three
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``*.conf`` files and add the option to them.
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``SampleMultiJvmNode1.conf``::
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akka.cluster.name = "test-cluster"
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``SampleMultiJvmNode2.conf``::
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akka.cluster.name = "test-cluster"
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``SampleMultiJvmNode3.conf``::
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akka.cluster.name = "test-cluster"
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ScalaTest
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=========
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There is also support for creating ScalaTest tests rather than applications. To
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do this use the same naming convention as above, but create ScalaTest suites
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rather than objects with main methods. You need to have ScalaTest on the
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classpath. Here is a similar example to the one above but using ScalaTest::
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package sample
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import org.scalatest.WordSpec
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import org.scalatest.matchers.MustMatchers
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class SpecMultiJvmNode1 extends WordSpec with MustMatchers {
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"A node" should {
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"be able to say hello" in {
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val message = "Hello from node 1"
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message must be("Hello from node 1")
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}
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}
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}
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class SpecMultiJvmNode2 extends WordSpec with MustMatchers {
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"A node" should {
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"be able to say hello" in {
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val message = "Hello from node 2"
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message must be("Hello from node 2")
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}
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}
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}
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To run just these tests you would call ``multi-jvm:test-only sample.Spec`` at
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the sbt prompt.
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ZookeeperBarrier
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================
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When running multi-JVM tests it's common to need to coordinate timing across
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nodes. To do this there is a ZooKeeper-based double-barrier (there is both an
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entry barrier and an exit barrier). ClusterNodes also have support for creating
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barriers easily. To wait at the entry use the ``enter`` method. To wait at the
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exit use the ``leave`` method. It's also possible t pass a block of code which
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will be run between the barriers.
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When creating a barrier you pass it a name and the number of nodes that are
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expected to arrive at the barrier. You can also pass a timeout. The default
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timeout is 60 seconds.
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Here is an example of coordinating the starting of two nodes and then running
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something in coordination::
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package sample
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import org.scalatest.WordSpec
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import org.scalatest.matchers.MustMatchers
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import org.scalatest.BeforeAndAfterAll
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import akka.cluster._
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object SampleMultiJvmSpec {
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val NrOfNodes = 2
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}
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class SampleMultiJvmNode1 extends WordSpec with MustMatchers with BeforeAndAfterAll {
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import SampleMultiJvmSpec._
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override def beforeAll() = {
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Cluster.startLocalCluster()
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}
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override def afterAll() = {
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Cluster.shutdownLocalCluster()
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}
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"A cluster" must {
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"have jvm options" in {
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System.getProperty("akka.cluster.nodename", "") must be("node1")
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System.getProperty("akka.cluster.port", "") must be("9991")
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akka.config.Config.config.getString("test.name", "") must be("node1")
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}
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"be able to start all nodes" in {
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LocalCluster.barrier("start", NrOfNodes) {
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Cluster.node.start()
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}
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Cluster.node.isRunning must be(true)
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Cluster.node.shutdown()
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}
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}
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}
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class SampleMultiJvmNode2 extends WordSpec with MustMatchers {
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import SampleMultiJvmSpec._
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"A cluster" must {
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"have jvm options" in {
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System.getProperty("akka.cluster.nodename", "") must be("node2")
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System.getProperty("akka.cluster.port", "") must be("9992")
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akka.config.Config.config.getString("test.name", "") must be("node2")
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}
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"be able to start all nodes" in {
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LocalCluster.barrier("start", NrOfNodes) {
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Cluster.node.start()
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}
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Cluster.node.isRunning must be(true)
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Cluster.node.shutdown()
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}
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}
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}
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An example output from this would be:
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.. code-block:: none
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> multi-jvm:test-only sample.Sample
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...
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[info] Starting JVM-Node1 for example.SampleMultiJvmNode1
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[info] Starting JVM-Node2 for example.SampleMultiJvmNode2
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[JVM-Node1] Loading config [akka.conf] from the application classpath.
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[JVM-Node2] Loading config [akka.conf] from the application classpath.
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...
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[JVM-Node2] Hello from node 2
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[JVM-Node1] Hello from node 1
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[success]
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NetworkFailureTest
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==================
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You can use the ``NetworkFailureTest`` trait to test network failure. See the
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``RemoteErrorHandlingNetworkTest`` test. Your tests needs to end with
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``NetworkTest``. They are disabled by default. To run them you need to enable a
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flag.
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Example::
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project akka-remote
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set akka.test.network true
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test-only akka.actor.remote.RemoteErrorHandlingNetworkTest
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It uses ``ipfw`` for network management. Mac OSX comes with it installed but if
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you are on another platform you might need to install it yourself. Here is a
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port:
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http://info.iet.unipi.it/~luigi/dummynet
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