diff --git a/apps/core/lib/core/domain/invoker.ex b/apps/core/lib/core/domain/invoker.ex
index 4d05a10f..043866b8 100644
--- a/apps/core/lib/core/domain/invoker.ex
+++ b/apps/core/lib/core/domain/invoker.ex
@@ -45,17 +45,20 @@ defmodule Core.Domain.Invoker do
   def invoke(ivk_pars) do
     Logger.info("Invoker: invocation for #{ivk_pars.module}/#{ivk_pars.function} requested")
 
-    # could be {:error, :no_workers}
-    with {:ok, worker} <- Nodes.worker_nodes() |> Scheduler.select() do
-      case invoke_without_code(worker, ivk_pars) do
-        {:error, :code_not_found} ->
-          worker
-          |> invoke_with_code(ivk_pars)
-          |> save_to_sinks(ivk_pars.module, ivk_pars.function)
-
-        res ->
-          save_to_sinks(res, ivk_pars.module, ivk_pars.function)
+    if Functions.exists_in_mod?(ivk_pars.function, ivk_pars.module) do
+      with {:ok, worker} <- Nodes.worker_nodes() |> Scheduler.select() do
+        case invoke_without_code(worker, ivk_pars) do
+          {:error, :code_not_found} ->
+            worker
+            |> invoke_with_code(ivk_pars)
+            |> save_to_sinks(ivk_pars.module, ivk_pars.function)
+
+          res ->
+            save_to_sinks(res, ivk_pars.module, ivk_pars.function)
+        end
       end
+    else
+      {:error, :not_found}
     end
   end
 
@@ -63,13 +66,8 @@ defmodule Core.Domain.Invoker do
           {:ok, InvokeResult.t()} | {:error, :code_not_found} | invoke_errors()
   def invoke_without_code(worker, ivk) do
     Logger.debug("Invoker: invoking #{ivk.module}/#{ivk.function} without code")
-
-    if Functions.exists_in_mod?(ivk.function, ivk.module) do
-      # send invocation without code
-      Commands.send_invoke(worker, ivk.function, ivk.module, ivk.args)
-    else
-      {:error, :not_found}
-    end
+    # send invocation without code
+    Commands.send_invoke(worker, ivk.function, ivk.module, ivk.args)
   end
 
   @spec invoke_with_code(atom(), InvokeParams.t()) ::
diff --git a/apps/core/test/core/integration/invoke_test.exs b/apps/core/test/core/integration/invoke_test.exs
index 3b85d59c..96ab9ed0 100644
--- a/apps/core/test/core/integration/invoke_test.exs
+++ b/apps/core/test/core/integration/invoke_test.exs
@@ -65,9 +65,13 @@ defmodule Core.InvokeTest do
       assert Invoker.invoke(pars) == {:error, {:exec_error, "some error"}}
     end
 
-    test "invoke should return {:error, :no_workers} when no workers are found" do
+    test "invoke should return {:error, :no_workers} when no workers are found", %{
+      function: function,
+      module: module
+    } do
       expected = {:error, :no_workers}
-      assert Invoker.invoke(%{"module" => "_", "function" => "test"}) == expected
+      pars = %InvokeParams{function: function.name, module: module.name}
+      assert Invoker.invoke(pars) == expected
     end
 
     test "invoke on node list with nodes other than workers should only use workers",
@@ -84,14 +88,19 @@ defmodule Core.InvokeTest do
       assert Invoker.invoke(pars) == {:ok, :worker@localhost}
     end
 
-    test "invoke on node list without workers should return {:error, no workers}" do
+    test "invoke on node list without workers should return {:error, no workers}",
+         %{
+           function: function,
+           module: module
+         } do
       Core.Cluster.Mock |> Mox.expect(:all_nodes, fn -> [:core@somewhere] end)
 
-      assert Invoker.invoke(%{"function" => "test"}) == {:error, :no_workers}
+      pars = %InvokeParams{function: function.name, module: module.name}
+      assert Invoker.invoke(pars) == {:error, :no_workers}
     end
 
     test "invoke on a non-existent function should return {:error, :not_found}" do
-      Core.Cluster.Mock |> Mox.expect(:all_nodes, fn -> [:worker@localhost] end)
+      Core.Cluster.Mock |> Mox.expect(:all_nodes, 0, fn -> [:worker@localhost] end)
 
       pars = %InvokeParams{function: "no_fun", module: "some module"}
       assert Invoker.invoke(pars) == {:error, :not_found}
diff --git a/apps/core/test/core_web/integration/controllers/function_controller_test.exs b/apps/core/test/core_web/integration/controllers/function_controller_test.exs
index 6ed5a7bf..64e615ee 100644
--- a/apps/core/test/core_web/integration/controllers/function_controller_test.exs
+++ b/apps/core/test/core_web/integration/controllers/function_controller_test.exs
@@ -422,13 +422,13 @@ defmodule CoreWeb.FunctionControllerTest do
     end
 
     test "renders error when function does not exist", %{conn: conn} do
-      Core.Cluster.Mock |> Mox.expect(:all_nodes, fn -> [:worker@localhost] end)
+      Core.Cluster.Mock |> Mox.expect(:all_nodes, 0, fn -> [:worker@localhost] end)
       conn = post(conn, Routes.function_path(conn, :invoke, "some_module", "no_function"))
       assert response(conn, 404)
     end
 
     test "renders error when module does not exist", %{conn: conn} do
-      Core.Cluster.Mock |> Mox.expect(:all_nodes, fn -> [:worker@localhost] end)
+      Core.Cluster.Mock |> Mox.expect(:all_nodes, 0, fn -> [:worker@localhost] end)
       conn = post(conn, Routes.function_path(conn, :invoke, "no_module", "some_function"))
       assert response(conn, 404)
     end