Set $window var based on currently active window

Previously $window was only set by the new_window() helper when it was
passed a name argument. This caused weird behavior cause if it was
called without a name it would simply attempt to recreate the same
window and fail. That was until @blueyed's fix in 2249cf8.

However, the $window var still wasn't being set correctly, leaving
split_v(), split_h() and other helpers to operate on the wrong
window. This is no longer an issue as $window is always set to the index
of the currently active window at the end of new_window() and
select_window().

test/lib/layout-helpers/new_window.test.sh

@@ -39,9 +39,20 @@ restore __go_to_window_or_session_path
 kill-test-session
 rm "/tmp/tmuxifier-new_window-test" &> /dev/null
 
-
-# Tear down.
-kill-test-server
+# When called ensure it sets the $window variable to the index of the newly
+# created window.
+unset window
+create-test-session
+stub __go_to_window_or_session_path
+new_window "foo"
+assert "echo $window" "1"
+new_window
+assert "echo $window" "2"
+new_window "bar"
+assert "echo $window" "3"
+restore __go_to_window_or_session_path
+kill-test-session
+unset window
 
 # End of tests.
 assert_end "new_window()"

test/lib/layout-helpers/select_window.test.sh

@@ -0,0 +1,55 @@
+#! /usr/bin/env bash
+source "../../test-helper.sh"
+source "${root}/lib/layout-helpers.sh"
+
+#
+# select_window() tests.
+#
+
+window_list() {
+  test-socket-tmux list-windows -t "$session:" \
+    -F "#{window_active}:#{window_index}" 2>/dev/null
+}
+
+# Selects given window when passed a window index
+create-test-session
+test-socket-tmux new-window -t "$session:1"
+test-socket-tmux new-window -t "$session:2"
+select_window 0
+assert "window_list | grep '^1:'" "1:0"
+select_window 1
+assert "window_list | grep '^1:'" "1:1"
+select_window 2
+assert "window_list | grep '^1:'" "1:2"
+kill-test-session
+
+# Selects given window when passed a window name
+create-test-session
+test-socket-tmux new-window -t "$session:1" -n "foo"
+test-socket-tmux new-window -t "$session:2" -n "bar"
+select_window foo
+assert "window_list | grep '^1:'" "1:1"
+select_window bar
+assert "window_list | grep '^1:'" "1:2"
+kill-test-session
+
+
+# When called ensure it sets the $window variable to the index of the newly
+# created window.
+unset window
+create-test-session
+test-socket-tmux new-window -t "$session:1" -n "foo"
+test-socket-tmux new-window -t "$session:2" -n "bar"
+select_window "foo"
+assert "echo $window" "1"
+select_window "bar"
+assert "echo $window" "2"
+select_window 1
+assert "echo $window" "1"
+select_window 2
+assert "echo $window" "2"
+kill-test-session
+unset window
+
+# End of tests.
+assert_end "select_window()"