diff --git a/modules/library/src/main/scala/zio/elasticsearch/ElasticExecutor.scala b/modules/library/src/main/scala/zio/elasticsearch/ElasticExecutor.scala
index 44f104a3d..52544d8ed 100644
--- a/modules/library/src/main/scala/zio/elasticsearch/ElasticExecutor.scala
+++ b/modules/library/src/main/scala/zio/elasticsearch/ElasticExecutor.scala
@@ -1,7 +1,8 @@
 package zio.elasticsearch
 
 import sttp.client3.SttpBackend
-import zio.{Task, ZIO, ZLayer}
+import zio.stm.TMap
+import zio.{Task, ULayer, ZIO, ZLayer}
 
 trait ElasticExecutor {
   def execute[A](request: ElasticRequest[A, _]): Task[A]
@@ -18,4 +19,7 @@ object ElasticExecutor {
 
   lazy val local: ZLayer[SttpBackend[Task, Any], Throwable, ElasticExecutor] =
     ZLayer.succeed(ElasticConfig.Default) >>> live
+
+  lazy val test: ULayer[TestExecutor] =
+    ZLayer(TMap.empty[IndexName, TMap[DocumentId, Document]].map(TestExecutor).commit)
 }
diff --git a/modules/library/src/main/scala/zio/elasticsearch/TestExecutor.scala b/modules/library/src/main/scala/zio/elasticsearch/TestExecutor.scala
new file mode 100644
index 000000000..b8e54dac2
--- /dev/null
+++ b/modules/library/src/main/scala/zio/elasticsearch/TestExecutor.scala
@@ -0,0 +1,129 @@
+package zio.elasticsearch
+
+import zio.Random.nextUUID
+import zio.elasticsearch.CreationOutcome.{AlreadyExists, Created}
+import zio.elasticsearch.DeletionOutcome.{Deleted, NotFound}
+import zio.elasticsearch.ElasticRequest._
+import zio.json.ast.Json
+import zio.stm.{STM, TMap, ZSTM}
+import zio.{Task, ZIO}
+
+private[elasticsearch] final case class TestExecutor private (data: TMap[IndexName, TMap[DocumentId, Document]])
+    extends ElasticExecutor {
+  self =>
+
+  override def execute[A](request: ElasticRequest[A, _]): Task[A] =
+    request match {
+      case CreateRequest(index, document, _, _) =>
+        fakeCreate(index, document)
+      case CreateWithIdRequest(index, id, document, _, _) =>
+        fakeCreateWithId(index, id, document)
+      case CreateIndexRequest(name, _) =>
+        fakeCreateIndex(name)
+      case CreateOrUpdateRequest(index, id, document, _, _) =>
+        fakeCreateOrUpdate(index, id, document)
+      case DeleteByIdRequest(index, id, _, _) =>
+        fakeDeleteById(index, id)
+      case DeleteIndexRequest(name) =>
+        fakeDeleteIndex(name)
+      case ExistsRequest(index, id, _) =>
+        fakeExists(index, id)
+      case GetByIdRequest(index, id, _) =>
+        fakeGetById(index, id)
+      case GetByQueryRequest(index, _, _) =>
+        fakeGetByQuery(index)
+      case map @ Map(_, _) =>
+        execute(map.request).flatMap(a => ZIO.fromEither(map.mapper(a)))
+    }
+
+  private def fakeCreate(index: IndexName, document: Document): Task[DocumentId] =
+    (for {
+      documents <- getDocumentsFromIndex(index)
+      documentId = DocumentId(nextUUID.toString)
+      _         <- documents.put(documentId, document)
+    } yield documentId).commit
+
+  private def fakeCreateWithId(index: IndexName, documentId: DocumentId, document: Document): Task[CreationOutcome] =
+    (for {
+      documents     <- getDocumentsFromIndex(index)
+      alreadyExists <- documents.contains(documentId)
+      _             <- documents.putIfAbsent(documentId, document)
+    } yield if (alreadyExists) AlreadyExists else Created).commit
+
+  private def fakeCreateIndex(index: IndexName): Task[CreationOutcome] =
+    (for {
+      alreadyExists  <- self.data.contains(index)
+      emptyDocuments <- TMap.empty[DocumentId, Document]
+      _              <- self.data.putIfAbsent(index, emptyDocuments)
+    } yield if (alreadyExists) AlreadyExists else Created).commit
+
+  private def fakeCreateOrUpdate(index: IndexName, documentId: DocumentId, document: Document): Task[Unit] =
+    (for {
+      documents <- getDocumentsFromIndex(index)
+      _         <- documents.put(documentId, document)
+    } yield ()).commit
+
+  private def fakeDeleteById(index: IndexName, documentId: DocumentId): Task[DeletionOutcome] =
+    (for {
+      documents <- getDocumentsFromIndex(index)
+      notExists <- documents.contains(documentId)
+      _         <- documents.delete(documentId)
+    } yield if (notExists) NotFound else Deleted).commit
+
+  private def fakeDeleteIndex(index: IndexName): Task[DeletionOutcome] =
+    (for {
+      notExists <- self.data.contains(index)
+      _         <- self.data.delete(index)
+    } yield if (notExists) NotFound else Deleted).commit
+
+  private def fakeExists(index: IndexName, documentId: DocumentId): Task[Boolean] =
+    (for {
+      documents <- getDocumentsFromIndex(index)
+      exists    <- documents.contains(documentId)
+    } yield exists).commit
+
+  private def fakeGetById(index: IndexName, documentId: DocumentId): Task[Option[Document]] =
+    (for {
+      documents     <- getDocumentsFromIndex(index)
+      maybeDocument <- documents.get(documentId)
+    } yield maybeDocument).commit
+
+  private def fakeGetByQuery(index: IndexName): Task[ElasticQueryResponse] = {
+    def createElasticQueryResponse(
+      index: IndexName,
+      documents: TMap[DocumentId, Document]
+    ): ZSTM[Any, Nothing, ElasticQueryResponse] = {
+      val shards = Shards(total = 1, successful = 1, skipped = 0, failed = 0)
+
+      for {
+        items <-
+          documents.toList.map(
+            _.map { case (id, document) =>
+              Item(
+                index = index.toString,
+                `type` = "type",
+                id = id.toString,
+                score = 1,
+                source = Json.Str(document.json)
+              )
+            }
+          )
+        hitsSize <- documents.size
+        hits      = Hits(total = Total(value = hitsSize, relation = ""), maxScore = 1, hits = items)
+      } yield ElasticQueryResponse(took = 1, timedOut = false, shards = shards, hits = hits)
+    }
+
+    (for {
+      documents <- getDocumentsFromIndex(index)
+      response  <- createElasticQueryResponse(index, documents)
+    } yield response).commit
+  }
+
+  private def getDocumentsFromIndex(index: IndexName): ZSTM[Any, ElasticException, TMap[DocumentId, Document]] =
+    for {
+      maybeDocuments <- self.data.get(index)
+      documents <- maybeDocuments.fold[STM[ElasticException, TMap[DocumentId, Document]]](
+                     STM.fail[ElasticException](new ElasticException(s"Index $index does not exists!"))
+                   )(STM.succeed(_))
+    } yield documents
+}