feat: make start session return an error tuple instead of raising

.gitignore

@@ -5,3 +5,4 @@ erl_crash.dump
 .DS_Store
 doc/
 screenshot-*.png
+.elixir_ls

lib/hound/helpers/session.ex

@@ -44,7 +44,7 @@ defmodule Hound.Helpers.Session do
     change_session_to(session_name)
     result = apply(func, [])
     change_session_to(previous_session_name)
-    result 
+    result
   end
 
 
@@ -117,9 +117,7 @@ defmodule Hound.Helpers.Session do
 
   @doc false
   def current_session_name do
-      Hound.SessionServer.current_session_name(self()) ||
-        raise "could not find a session for process #{inspect self()}"
-
-
+    Hound.SessionServer.current_session_name(self()) ||
+      raise "could not find a session for process #{inspect self()}"
   end
 end

lib/hound/session_server.ex

@@ -10,7 +10,7 @@ defmodule Hound.SessionServer do
 
 
   def session_for_pid(pid, opts) do
-    current_session_id(pid) ||
+    {:ok, current_session_id(pid)} ||
       change_current_session_for_pid(pid, :default, opts)
   end
 
@@ -58,34 +58,49 @@ defmodule Hound.SessionServer do
     {:ok, state}
   end
 
+  def handle_call({:destroy_sessions, pid}, _from, state) do
+    destroy_sessions(pid)
+    {:reply, :ok, state}
+  end
 
   def handle_call({:change_session, pid, session_name, opts}, _from, state) do
-    {:ok, driver_info} = Hound.driver_info
-
-    {ref, sessions} =
-      case :ets.lookup(@name, pid) do
-        [{^pid, ref, _session_id, sessions}] ->
-          {ref, sessions}
-        [] ->
-          {Process.monitor(pid), %{}}
-      end
-
-    {session_id, sessions} =
-      case Map.fetch(sessions, session_name) do
-        {:ok, session_id} ->
-          {session_id, sessions}
-        :error ->
-          session_id = create_session(driver_info, opts)
-          {session_id, Map.put(sessions, session_name, session_id)}
-      end
+    {ref, sessions} = case :ets.lookup(@name, pid) do
+      [{^pid, ref, _session_id, sessions}] ->
+        {ref, sessions}
+      [] ->
+        {Process.monitor(pid), %{}}
+    end
+
+
+    case find_existing_session(sessions, session_name) do
+      {:ok, {session_id, sessions}} ->
+        add_session_to_table(pid, ref, session_id, sessions)
+
+        {:reply, {:ok, session_id}, Map.put(state, ref, pid)}
+
+      :error ->
+        {:ok, driver_info} = Hound.driver_info()
+
+        case create_session(driver_info, opts) do
+          {:error, _} = e -> {:reply, e, state}
 
+          {:ok, session_id} ->
+            sessions = Map.put(sessions, session_name, session_id)
+            add_session_to_table(pid, ref, session_id, sessions)
+
+            {:reply, {:ok, session_id}, Map.put(state, ref, pid)}
+        end
+    end
+  end
+
+  defp add_session_to_table(pid, ref, session_id, sessions) do
     :ets.insert(@name, {pid, ref, session_id, sessions})
-    {:reply, session_id, Map.put(state, ref, pid)}
   end
 
-  def handle_call({:destroy_sessions, pid}, _from, state) do
-    destroy_sessions(pid)
-    {:reply, :ok, state}
+  defp find_existing_session(sessions, session_name) do
+    with {:ok, session_id} <- Map.fetch(sessions, session_name) do
+       {:ok, {session_id, sessions}}
+    end
   end
 
   def handle_info({:DOWN, ref, _, _, _}, state) do
@@ -96,10 +111,7 @@ defmodule Hound.SessionServer do
   end
 
   defp create_session(driver_info, opts) do
-    case Hound.Session.create_session(driver_info[:browser], opts) do
-      {:ok, session_id} -> session_id
-      {:error, reason} -> raise "could not create a new session: #{reason}, check webdriver is running"
-    end
+    Hound.Session.create_session(driver_info[:browser], opts)
   end
 
   defp destroy_sessions(pid) do