Add simple test to avoid regressions

spec/integrations/rebound_bracket_spec.rb

@@ -0,0 +1,14 @@
+describe 'rebinding [' do
+  context 'initialized before sourcing the plugin' do
+    before do
+      session.send_string("function [ { test \"$@\" }")
+      session.send_keys("'enter'")
+      session.run_command("clear")
+    end
+
+    it 'executes the custom behavior and the built-in behavior' do
+      session.send_string('asdf')
+      wait_for { session.content }.to eq('asdf')
+    end
+  end
+end