add process state

lib/database_server.ex

@@ -1,6 +1,9 @@
 defmodule DatabaseServer do
   def start do
-    spawn(&loop/0)
+    spawn(fn ->
+        connection = :random.uniform(1000)
+        loop(connection)
+      end)
   end
 
   def run_async(server_pid, query_def) do
@@ -11,21 +14,21 @@ defmodule DatabaseServer do
     receive do
       {:query_result, result} -> result
     after 5000 ->
-      {:error, :timeout}  
+      {:error, :timeout}
     end
   end
 
-  defp loop do
+  defp loop(connection) do
     receive do
       {:run_query, caller, query_def} ->
-        send(caller, {:query_result, run_query(query_def)})
+        send(caller, {:query_result, run_query(connection, query_def)})
     end
 
-    loop
+    loop(connection)
   end
 
-  defp run_query(query_def) do
-    "#{query_def} result"
+  defp run_query(connection, query_def) do
+    "Connection #{connection}: #{query_def} result"
   end
 
 end

test/database_server_test.exs

@@ -4,7 +4,9 @@ defmodule DatabaseServerTest do
   test "database" do
     DatabaseServer.start
     |> DatabaseServer.run_async("query 1")
-    assert DatabaseServer.get_result == "query 1 result"
+    actual = DatabaseServer.get_result
+    assert String.starts_with? actual, "Connection "
+    assert String.ends_with? actual, " 1 result"
   end
 
   test "pull 100 servers" do
@@ -19,9 +21,12 @@ defmodule DatabaseServerTest do
       DatabaseServer.run_async(server_pid, query_def)
     end)
 
-    assert 1..5
+    actual = 1..5
     |> Enum.map(fn(_) -> DatabaseServer.get_result end)
-    |> Enum.sort == ["1 result", "2 result", "3 result", "4 result", "5 result"]
+    Enum.each(actual, fn(x) ->
+      assert String.starts_with? x, "Connection "
+      assert String.ends_with? x, " result"
+    end)
   end
 
 end