diff --git a/lib/rage/cli.rb b/lib/rage/cli.rb
index 371d387..9983d6d 100644
--- a/lib/rage/cli.rb
+++ b/lib/rage/cli.rb
@@ -4,6 +4,23 @@
 require "rack"
 require "rage/version"
 
+# mock fiber methods as RSpec tests don't run concurrently
+class Fiber
+  def self.schedule(&block)
+    fiber = Fiber.new(blocking: true) do
+      Fiber.current.__set_id
+      Fiber.current.__set_result(block.call)
+    end
+    fiber.resume
+
+    fiber
+  end
+
+  def self.await(fibers)
+    Array(fibers).map(&:__get_result)
+  end
+end
+
 module Rage
   class CLICodeGenerator < Thor
     include Thor::Actions