return name of performance

and don't send any empty performances

lib/conductor.ex

@@ -12,6 +12,7 @@ defmodule Grengine.Conductor do
     |> Enum.map( fn perf ->
       do_performance(perf)
     end)
+    |> Enum.reject( fn val -> is_nil(val) end)
   end
 
 
@@ -24,7 +25,11 @@ defmodule Grengine.Conductor do
 
   def do_performance(perf) do
     [{_n, _l, {:performance, name}}, _pid, :undefined] = perf
-    Performance.get_values(name)
+    values = Performance.get_values(name)
+    case length( Map.keys(values)) do
+      0  -> nil
+      _  ->  %{name => Performance.get_values(name)}
+    end
   end
 
 

lib/grain.ex

 defmodule Grengine.Grain do
 
-  alias Grengine.{Grain, Parameter}
 
 
   def start_link() do
@@ -21,7 +20,7 @@ defmodule Grengine.Grain do
   end
 
 
-  def to_string(grain) do
+  def to_string(_grain) do
     "{}"
   end
 

lib/performance.ex

@@ -3,7 +3,6 @@ defmodule Grengine.Performance do
   use GenServer
 
 
-  alias Grengine.Performance
   alias Grengine.Grain
 
   def start_link(name) do
@@ -28,7 +27,7 @@ defmodule Grengine.Performance do
 
   # SERVER
 
-  def init(params) do
+  def init(_params) do
     {:ok, grain} = Grain.start_link()
     {:ok, grain}
   end
@@ -50,7 +49,7 @@ defmodule Grengine.Performance do
     {:reply, Grain.get_values(grain), grain}
   end
 
-  def to_string(performance) do
+  def to_string(_performance) do
     "Performance"
   end
 

test/conductor_test.exs

@@ -2,7 +2,7 @@ defmodule ConductorTest do
 
   use ExUnit.Case, async: true
 
-  alias Grengine.{Conductor, PerformanceSupervisor}
+  alias Grengine.{Conductor, Performance, PerformanceSupervisor}
 
   describe "finding all performances" do
 
@@ -10,6 +10,7 @@ defmodule ConductorTest do
       PerformanceSupervisor.start_link
       PerformanceSupervisor.start_performance("foo")
       PerformanceSupervisor.start_performance("bar")
+      Performance.set_values("foo", %{s1: 42})
       :ok
 
     end
@@ -24,6 +25,7 @@ defmodule ConductorTest do
     test "handle single performance" do
       values = Conductor.perform()
       assert is_list(values)
+      assert length(values) == 1
     end
 
   end