feat: add test for multiple overrides config files

app/src/main/kotlin/maru/app/MaruApp.kt

@@ -41,6 +41,10 @@ import org.hyperledger.besu.plugin.services.MetricsSystem
 import org.web3j.protocol.Web3j
 import tech.pegasys.teku.ethereum.executionclient.web3j.Web3JClient
 
+interface LongRunningCloseable :
+  LongRunningService,
+  AutoCloseable
+
 class MaruApp(
   val config: MaruConfig,
   val beaconGenesisConfig: ForksSchedule,
@@ -58,7 +62,7 @@ class MaruApp(
   private val apiServer: ApiServer,
   private val syncStatusProvider: SyncStatusProvider,
   private val syncControllerManager: LongRunningService,
-) : AutoCloseable {
+) : LongRunningCloseable {
   private val log: Logger = LogManager.getLogger(this.javaClass)
 
   private fun getPrivateKeyWithoutPrefix() = Crypto.privateKeyBytesWithoutPrefix(privateKeyProvider())
@@ -112,7 +116,7 @@ class MaruApp(
       privateKeyWithoutPrefix = getPrivateKeyWithoutPrefix(),
     )
 
-  fun start() {
+  override fun start() {
     if (finalizationProvider is LineaFinalizationProvider) {
       start("Finalization Provider", finalizationProvider::start)
     }
@@ -128,7 +132,7 @@ class MaruApp(
     log.info("Maru is up")
   }
 
-  fun stop() {
+  override fun stop() {
     stop("Sync service", syncControllerManager::stop)
     stop("P2P Network") { p2pNetwork.stop().get() }
     if (finalizationProvider is LineaFinalizationProvider) {

app/src/main/kotlin/maru/app/MaruAppCli.kt

@@ -56,17 +56,22 @@ enum class Network(
   descriptionHeading = "%nDescription:%n%n",
   optionListHeading = "%nOptions:%n",
   footerHeading = "%n",
+  mixinStandardHelpOptions = true,
 )
 class MaruAppCli(
-  private val dryRun: Boolean = false,
+  private val maruAppFactory: MaruAppFactoryCreator = MaruAppFactory(),
 ) : Callable<Int> {
   private val log = LogManager.getLogger(this.javaClass)
 
   @Option(
     names = ["--config"],
-    paramLabel = "CONFIG.toml,CONFIG.overrides.toml",
-    description = ["Configuration files"],
+    paramLabel = "CONFIG.toml",
+    description = [
+      "Comma-separated list of configuration files or in multiple options" +
+        " e.g. \"--config=CONFIG.toml --config=CONFIG.overrides.toml\"",
+    ],
     arity = "1..*",
+    split = ",",
     required = true,
   )
   val configFiles: List<File>? = null
@@ -116,33 +121,32 @@ class MaruAppCli(
       log.info("Using the genesis file of the named network \"${genesisOptions!!.network!!.networkNameInKebab}\"")
     }
 
-    if (!dryRun) {
-      val parsedAppConfig = MaruConfigLoader.loadAppConfigs(configFiles)
-      val parsedBeaconGenesisConfig = MaruConfigLoader.loadGenesisConfig(genesisOptions!!.genesisFile!!)
-      val app =
-        MaruAppFactory()
-          .create(
-            config = parsedAppConfig.domainFriendly(),
-            beaconGenesisConfig = parsedBeaconGenesisConfig.domainFriendly(),
-          )
-      app.start()
+    val parsedAppConfig = MaruConfigLoader.loadAppConfigs(configFiles)
+    val parsedBeaconGenesisConfig = MaruConfigLoader.loadGenesisConfig(genesisOptions!!.genesisFile!!)
 
-      Runtime
-        .getRuntime()
-        .addShutdownHook(
-          Thread {
-            app.stop()
-            if (LogManager.getContext() is LoggerContext) {
-              // Disable log4j auto shutdown hook is not used otherwise
-              // Messages in App.stop won't appear in the logs
-              Configurator.shutdown(LogManager.getContext() as LoggerContext)
-            }
-          },
-        )
-    }
+    val app =
+      maruAppFactory.create(
+        config = parsedAppConfig.domainFriendly(),
+        beaconGenesisConfig = parsedBeaconGenesisConfig.domainFriendly(),
+      )
+    app.start()
+
+    Runtime
+      .getRuntime()
+      .addShutdownHook(
+        Thread {
+          app.stop()
+          app.close()
+          if (LogManager.getContext() is LoggerContext) {
+            // Disable log4j auto shutdown hook is not used otherwise
+            // Messages in App.stop won't appear in the logs
+            Configurator.shutdown(LogManager.getContext() as LoggerContext)
+          }
+        },
+      )
 
     return 0
   }
 
-  private fun validateFileCanRead(file: File): Boolean = dryRun || file.canRead()
+  private fun validateFileCanRead(file: File): Boolean = file.canRead()
 }

app/src/main/kotlin/maru/app/MaruAppFactory.kt

@@ -82,9 +82,7 @@ import tech.pegasys.teku.ethereum.executionclient.web3j.Web3JClient
 import tech.pegasys.teku.networking.p2p.network.config.GeneratingFilePrivateKeySource
 import org.hyperledger.besu.plugin.services.MetricsSystem as BesuMetricsSystem
 
-class MaruAppFactory {
-  private val log = LogManager.getLogger(this.javaClass)
-
+interface MaruAppFactoryCreator {
   fun create(
     config: MaruConfig,
     beaconGenesisConfig: ForksSchedule,
@@ -107,7 +105,35 @@ class MaruAppFactory {
       P2PState,
       () -> SyncStatusProvider,
     ) -> P2PNetworkImpl = ::P2PNetworkImpl,
-  ): MaruApp {
+  ): LongRunningCloseable
+}
+
+class MaruAppFactory : MaruAppFactoryCreator {
+  private val log = LogManager.getLogger(this.javaClass)
+
+  override fun create(
+    config: MaruConfig,
+    beaconGenesisConfig: ForksSchedule,
+    clock: Clock,
+    overridingP2PNetwork: P2PNetwork?,
+    overridingFinalizationProvider: FinalizationProvider?,
+    overridingLineaContractClient: LineaRollupSmartContractClientReadOnly?,
+    overridingApiServer: ApiServer?,
+    p2pNetworkFactory: (
+      ByteArray,
+      P2PConfig,
+      UInt,
+      SerDe<SealedBeaconBlock>,
+      MetricsFacade,
+      BesuMetricsSystem,
+      StatusManager,
+      BeaconChain,
+      ForkPeeringManager,
+      () -> Boolean,
+      P2PState,
+      () -> SyncStatusProvider,
+    ) -> P2PNetworkImpl,
+  ): LongRunningCloseable {
     log.info("configs={}", config)
     log.info("beaconGenesisConfig={}", beaconGenesisConfig)