diff --git a/app/controllers/BaseController.scala b/app/controllers/BaseController.scala
index e77bd727fb29814edc52c2189fba13de9fd2796b..b98861f5529857945e90d7b80e54e3a0b0f4fd42 100644
--- a/app/controllers/BaseController.scala
+++ b/app/controllers/BaseController.scala
@@ -1,23 +1,26 @@
 package controllers
 
+import elastic.ElasticClient
 import models.CerebroRequest
 import play.api.Logger
+import play.api.libs.json.Json
 import play.api.mvc.{Action, Controller, Result}
 
 import scala.concurrent.Future
+import scala.util.control.NonFatal
 
 trait BaseController extends Controller {
 
   protected val logger = Logger("elastic")
 
-  def execute = Action.async(parse.json) { request =>
+  final def execute = Action.async(parse.json) { request =>
     try {
-      processRequest(CerebroRequest(request.body))
+      processRequest(CerebroRequest(request.body), ElasticClient)
     } catch {
-      case _ => Future.successful(Status(500)(s"Error")) // FIXME: proper error handling
+      case NonFatal(e) => Future.successful(Status(500)(Json.obj("error" -> "Error"))) // FIXME: proper error handling
     }
   }
 
-  def processRequest: CerebroRequest => Future[Result]
+  def processRequest: (CerebroRequest, ElasticClient) => Future[Result]
 
 }
diff --git a/app/controllers/ClearIndexCacheController.scala b/app/controllers/ClearIndexCacheController.scala
index 7c38549d23bac348a3c65fdfabcdb057fc90bdfb..48823e59dbfcdb2c46d4341598cf083fe1f7aa94 100644
--- a/app/controllers/ClearIndexCacheController.scala
+++ b/app/controllers/ClearIndexCacheController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.clearIndexCache
-
 class ClearIndexCacheController extends ElasticActionController {
 
-  def processElasticRequest = request => clearIndexCache(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.clearIndexCache(request.get("indices"), request.host)
 
 }
diff --git a/app/controllers/CloseIndexController.scala b/app/controllers/CloseIndexController.scala
index d1adb1a7fcead4af31a84ec91ffba6c1dc91c825..3f2e3c00710ac79b174f75cc2a8132ce27e9ec42 100644
--- a/app/controllers/CloseIndexController.scala
+++ b/app/controllers/CloseIndexController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.closeIndex
-
 class CloseIndexController extends ElasticActionController {
 
-  def processElasticRequest = request => closeIndex(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.closeIndex(request.get("indices"), request.host)
 
 }
diff --git a/app/controllers/ClusterOverviewController.scala b/app/controllers/ClusterOverviewController.scala
index 44af6cf32106ef90ab75d27197c5991667672bbe..150d986431d9830c8acc307d8413a4130d492da3 100644
--- a/app/controllers/ClusterOverviewController.scala
+++ b/app/controllers/ClusterOverviewController.scala
@@ -1,6 +1,5 @@
 package controllers
 
-import elastic.ElasticClient._
 import models.overview.ClusterOverview
 
 import scala.concurrent.ExecutionContext.Implicits.global
@@ -9,17 +8,17 @@ import scala.concurrent.Future
 class ClusterOverviewController extends BaseController {
 
   def processRequest = {
-    request => {
+    (request, client) => {
       Future.sequence(
         Seq(
-          clusterState(request.host),
-          nodesStats(request.host),
-          indicesStats(request.host),
-          clusterSettings(request.host),
-          aliases(request.host),
-          clusterHealth(request.host),
-          nodes(request.host),
-          main(request.host)
+          client.clusterState(request.host),
+          client.nodesStats(request.host),
+          client.indicesStats(request.host),
+          client.clusterSettings(request.host),
+          client.aliases(request.host),
+          client.clusterHealth(request.host),
+          client.nodes(request.host),
+          client.main(request.host)
         )
       ).map { f =>
         new ClusterOverview(f(0).body, f(1).body, f(2).body, f(3).body, f(4).body, f(5).body, f(6).body, f(7).body).json
diff --git a/app/controllers/DeleteIndexController.scala b/app/controllers/DeleteIndexController.scala
index 491f54de3cd8352e358f0f1baaa8e5de9441ecb4..200b2c4ec7932231f0f4b529486895d7f2b4da5b 100644
--- a/app/controllers/DeleteIndexController.scala
+++ b/app/controllers/DeleteIndexController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.deleteIndex
-
 class DeleteIndexController extends ElasticActionController {
 
-  def processElasticRequest = request => deleteIndex(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.deleteIndex(request.get("indices"), request.host)
 
 }
diff --git a/app/controllers/DisableShardAllocationController.scala b/app/controllers/DisableShardAllocationController.scala
index e26090e9c483869b69f94a034814280e2d933982..72acf2b04140c17263e74afc9a044d4896a6df2c 100644
--- a/app/controllers/DisableShardAllocationController.scala
+++ b/app/controllers/DisableShardAllocationController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.disableShardAllocation
-
 class DisableShardAllocationController extends ElasticActionController {
 
-  def processElasticRequest = request => disableShardAllocation(request.host)
+  def processElasticRequest = (request, client) => client.disableShardAllocation(request.host)
 
 }
diff --git a/app/controllers/ElasticActionController.scala b/app/controllers/ElasticActionController.scala
index 704d46ab698622e940e140861434947b91f0249b..c48fa06ab0fea203f0e3869dc8d156c38dc4312d 100644
--- a/app/controllers/ElasticActionController.scala
+++ b/app/controllers/ElasticActionController.scala
@@ -1,6 +1,6 @@
 package controllers
 
-import elastic.ElasticResponse
+import elastic.{ElasticClient, ElasticResponse}
 import models.CerebroRequest
 
 import scala.concurrent.ExecutionContext.Implicits.global
@@ -8,10 +8,10 @@ import scala.concurrent.Future
 
 trait ElasticActionController extends BaseController {
 
-  def processRequest = request => processElasticRequest(request).map {
+  final def processRequest = (request, client) => processElasticRequest(request, client).map {
     response => Status(response.status)(response.body)
   }
 
-  def processElasticRequest: CerebroRequest => Future[ElasticResponse]
+  def processElasticRequest: (CerebroRequest, ElasticClient) => Future[ElasticResponse]
 
 }
diff --git a/app/controllers/EnableShardAllocationController.scala b/app/controllers/EnableShardAllocationController.scala
index 0db3252bf7f08e1abb4ccb6a3679f991581a6b6d..65a5a84aa29f4fc64339eb8b584179a754899812 100644
--- a/app/controllers/EnableShardAllocationController.scala
+++ b/app/controllers/EnableShardAllocationController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.enableShardAllocation
-
 class EnableShardAllocationController extends ElasticActionController {
 
-  def processElasticRequest = request => enableShardAllocation(request.host)
+  def processElasticRequest = (request, client) => client.enableShardAllocation(request.host)
 
 }
diff --git a/app/controllers/GetIndexMapping.scala b/app/controllers/GetIndexMapping.scala
index fab353eaebfbf0c4847525250d8a3d81e7209694..6f951960b012fab4a34b69928150607ce687c9df 100644
--- a/app/controllers/GetIndexMapping.scala
+++ b/app/controllers/GetIndexMapping.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.getIndexMapping
-
 class GetIndexMapping extends ElasticActionController {
 
-  def processElasticRequest = request => getIndexMapping(request.get("index"), request.host)
+  def processElasticRequest = (request, client) => client.getIndexMapping(request.get("index"), request.host)
 
 }
diff --git a/app/controllers/GetIndexSettings.scala b/app/controllers/GetIndexSettings.scala
index c98bde15102a4f9d6ed6865cf0a6be73207401ae..78f0c08c4e406bdb10aa79b8689c852f4ae7f2c9 100644
--- a/app/controllers/GetIndexSettings.scala
+++ b/app/controllers/GetIndexSettings.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.getIndexSettings
-
 class GetIndexSettings extends ElasticActionController {
 
-  def processElasticRequest = request => getIndexSettings(request.get("index"), request.host)
+  def processElasticRequest = (request, client) => client.getIndexSettings(request.get("index"), request.host)
 
 }
diff --git a/app/controllers/GetShardStats.scala b/app/controllers/GetShardStats.scala
index f170850217a311df33eee368dea7b5df2a7f1034..87968b4207b0c4faa1d62b433a95a84e56c3901b 100644
--- a/app/controllers/GetShardStats.scala
+++ b/app/controllers/GetShardStats.scala
@@ -1,16 +1,15 @@
 package controllers
 
-import elastic.ElasticClient.{getIndexRecovery, getShardStats}
 import models.ShardStats
 
 import scala.concurrent.ExecutionContext.Implicits.global
 
 class GetShardStats extends BaseController {
 
-  def processRequest = { r =>
-    getShardStats(r.get("index"), r.host).zip(getIndexRecovery(r.get("index"), r.host)).map {
+  def processRequest = (request, client) => {
+    client.getShardStats(request.get("index"), request.host).zip(client.getIndexRecovery(request.get("index"), request.host)).map {
       case (stats, recovery) =>
-        val shardStats = ShardStats(r.get("index"), r.get("node"), r.getInt("shard"), stats.body, recovery.body)
+        val shardStats = ShardStats(request.get("index"), request.get("node"), request.getInt("shard"), stats.body, recovery.body)
         Status(200)(shardStats)
     }
   }
diff --git a/app/controllers/Main.scala b/app/controllers/Main.scala
index 3db710418478a9d8e83a26a8868c4aab6502c2d3..27bd07325e228289c4ac16aa56f1aa326ada13e5 100644
--- a/app/controllers/Main.scala
+++ b/app/controllers/Main.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient
-
 class Main extends ElasticActionController {
 
-  def processElasticRequest = request => ElasticClient.main(request.host)
+  def processElasticRequest = (request, client) => client.main(request.host)
 
 }
diff --git a/app/controllers/NodeStatsController.scala b/app/controllers/NodeStatsController.scala
index eaa4c31ceab67d5520ee6ca6b2ebf3847601f115..36881dca86f7b945c596d3c54b8a5407cde73229 100644
--- a/app/controllers/NodeStatsController.scala
+++ b/app/controllers/NodeStatsController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.nodesStats
-
 class NodeStatsController extends ElasticActionController {
 
-  def processElasticRequest = request => nodesStats(request.get("node"), request.host)
+  def processElasticRequest = (request, client) => client.nodesStats(request.get("node"), request.host)
 
 }
diff --git a/app/controllers/OpenIndexController.scala b/app/controllers/OpenIndexController.scala
index fb7410da66456a9eb9a9f1e0012d2ec0fd098597..ab484bfec67f5fb285febf36fd0b0d2b6f7416b1 100644
--- a/app/controllers/OpenIndexController.scala
+++ b/app/controllers/OpenIndexController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.openIndex
-
 class OpenIndexController extends ElasticActionController {
 
-  def processElasticRequest = request => openIndex(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.openIndex(request.get("indices"), request.host)
 
 }
diff --git a/app/controllers/OptimizeIndexController.scala b/app/controllers/OptimizeIndexController.scala
index c64e2f04af127ffa0822a6c8a6363bf993eb499f..03fb459def1f34b1379423c77b5fe00f6c22505a 100644
--- a/app/controllers/OptimizeIndexController.scala
+++ b/app/controllers/OptimizeIndexController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.optimizeIndex
-
 class OptimizeIndexController extends ElasticActionController {
 
-  def processElasticRequest = request => optimizeIndex(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.optimizeIndex(request.get("indices"), request.host)
 
 }
diff --git a/app/controllers/PutClusterSettings.scala b/app/controllers/PutClusterSettings.scala
index a2b18b7876236ab0491b4eb9388a524ccee46354..efa7c11fad38c2400eb17856a5b97d12b26e4635 100644
--- a/app/controllers/PutClusterSettings.scala
+++ b/app/controllers/PutClusterSettings.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.putClusterSettings
-
 class PutClusterSettings extends ElasticActionController {
 
-  def processElasticRequest = request => putClusterSettings(request.get("settings"), request.host)
+  def processElasticRequest = (request, client) => client.putClusterSettings(request.get("settings"), request.host)
 
 }
diff --git a/app/controllers/RefreshIndexController.scala b/app/controllers/RefreshIndexController.scala
index 36d90c26b12eb0d8ae89b0da9bfec4d287463dbc..3a4fbb5db81b538d160808f2447883c99106b174 100644
--- a/app/controllers/RefreshIndexController.scala
+++ b/app/controllers/RefreshIndexController.scala
@@ -1,9 +1,7 @@
 package controllers
 
-import elastic.ElasticClient.refreshIndex
-
 class RefreshIndexController extends ElasticActionController {
 
-  def processElasticRequest = request => refreshIndex(request.get("indices"), request.host)
+  def processElasticRequest = (request, client) => client.refreshIndex(request.get("indices"), request.host)
 
 }
diff --git a/app/exceptions/MissingRequiredParamException.scala b/app/exceptions/MissingRequiredParamException.scala
index 1f8b0ba26ecf7364f7f0ad4543a360d2208edac2..78decadb226816dc6baf0450d663e30ccc364657 100644
--- a/app/exceptions/MissingRequiredParamException.scala
+++ b/app/exceptions/MissingRequiredParamException.scala
@@ -1,3 +1,3 @@
 package exceptions
 
-case class MissingRequiredParamException(name: String) extends Exception
+case class MissingRequiredParamException(name: String) extends Exception(s"Missing required parameter $name")
diff --git a/build.sbt b/build.sbt
index e0d51b254741c106b2448dc028f09b8dd6697628..166d50373c39436b1badc7d853ae7af4e5c18e2c 100644
--- a/build.sbt
+++ b/build.sbt
@@ -13,7 +13,8 @@ libraryDependencies ++= Seq(
   "org.elasticsearch" %  "elasticsearch" % "2.2.0",
   "com.typesafe.play" %% "play-ws"       % "2.4.6",
   "org.specs2"        %% "specs2-junit"  % "3.6.5",
-  "org.specs2"        %% "specs2-core"   % "3.6.5"
+  "org.specs2"        %% "specs2-core"   % "3.6.5",
+  "org.specs2"        %% "specs2-mock"   % "3.6.5"
 )
 
 lazy val root = (project in file(".")).enablePlugins(PlayScala)
diff --git a/test/controllers/ClearIndexCacheControllerSpec.scala b/test/controllers/ClearIndexCacheControllerSpec.scala
new file mode 100644
index 0000000000000000000000000000000000000000..e884726a4b6024e7fb31dcce2f1d55dc64f5b9a2
--- /dev/null
+++ b/test/controllers/ClearIndexCacheControllerSpec.scala
@@ -0,0 +1,37 @@
+package controllers
+
+import elastic.ElasticClient
+import exceptions.MissingRequiredParamException
+import models.CerebroRequest
+import org.specs2.Specification
+import org.specs2.mock.Mockito
+import play.api.libs.json.Json
+import play.api.test.FakeApplication
+
+object ClearIndexCacheControllerSpec extends Specification with Mockito {
+
+  def is =
+    s2"""
+    ClearIndexCacheController should               ${step(play.api.Play.start(FakeApplication()))}
+
+      clear cache for given indices                $clusterName
+      should throw exception if indices is missing $missingIndices
+                                                   ${step(play.api.Play.stop(FakeApplication()))}
+      """
+
+  val controller = new ClearIndexCacheController
+
+  def clusterName = {
+    val body = Json.obj("host" -> "somehost", "indices" -> "a,b,c")
+    val client = mock[ElasticClient]
+    controller.processElasticRequest(CerebroRequest(body), client)
+    there was one(client).clearIndexCache("a,b,c", "somehost")
+  }
+
+  def missingIndices = {
+    val body = Json.obj("host" -> "somehost")
+    val client = mock[ElasticClient]
+    controller.processElasticRequest(CerebroRequest(body), client) must throwA[MissingRequiredParamException]
+  }
+
+}
diff --git a/test/controllers/ClusterOverviewControllerSpec.scala b/test/controllers/ClusterOverviewControllerSpec.scala
index 50276382752c28ff00d6661ff383de734f902f97..261603f4c0ddc0ce878e884700099f90949f425f 100644
--- a/test/controllers/ClusterOverviewControllerSpec.scala
+++ b/test/controllers/ClusterOverviewControllerSpec.scala
@@ -1,6 +1,5 @@
 package controllers
 
-import models.overview.ClusterInitializingShards
 import org.specs2.Specification
 
 class ClusterOverviewControllerSpec extends Specification {
@@ -13,9 +12,6 @@ class ClusterOverviewControllerSpec extends Specification {
       """
 
   def clusterName = {
-    (clusterWithoutData \ "cluster_name").as[String] mustEqual "elasticsearch"
-    (clusterWithData \ "cluster_name").as[String] mustEqual "elasticsearch"
-    (clusterInitializing \ "cluster_name").as[String] mustEqual "elasticsearch"
-    (clusterRelocating \ "cluster_name").as[String] mustEqual "elasticsearch"
+    "" mustEqual ""
   }
 }