diff --git a/spec/terminal_session.rb b/spec/terminal_session.rb
index 275a90b..a089d27 100644
--- a/spec/terminal_session.rb
+++ b/spec/terminal_session.rb
@@ -12,7 +12,9 @@ class TerminalSession
       zsh_bin: ZSH_BIN
     }.merge(opts)
 
-    cmd="PS1=#{opts[:prompt]} TERM=#{opts[:term]} #{ZSH_BIN} -f"
+    @opts = opts
+
+    cmd="PS1=\"#{opts[:prompt]}\" TERM=#{opts[:term]} #{ZSH_BIN} -f"
     tmux_command("new-session -d -x #{opts[:width]} -y #{opts[:height]} '#{cmd}'")
   end
 
@@ -66,6 +68,8 @@ class TerminalSession
 
   private
 
+  attr_reader :opts
+
   def tmux_socket_name
     @tmux_socket_name ||= SecureRandom.hex(6)
   end