Refactor Pry.toplevel_binding to allow reset during tests

lib/pry/pry_class.rb

@@ -390,16 +390,23 @@ class Pry
       end
     end
   end
-end
 
-# Grab a copy of the TOPLEVEL_BINDING without any local variables.
-# This binding has a default definee of Object, and new methods are
-# private (just as in TOPLEVEL_BINDING).
-def self.__pry__
+  def self.toplevel_binding
+    unless @toplevel_binding
+      # Grab a copy of the TOPLEVEL_BINDING without any local variables.
+      # This binding has a default definee of Object, and new methods are
+      # private (just as in TOPLEVEL_BINDING).
+      TOPLEVEL_BINDING.eval <<-RUBY
+        def self.__pry__
           binding
+        end
+        Pry.toplevel_binding = __pry__
+        class << self; undef __pry__; end
+      RUBY
+    end
+    @toplevel_binding.eval('private')
+    @toplevel_binding
+  end
 end
-Pry.toplevel_binding = __pry__
-Pry.toplevel_binding.eval("private")
-class << self; undef __pry__; end
 
 Pry.init

test/helper.rb

@@ -49,6 +49,17 @@ module Bacon
   end
 end
 
+# Reset toplevel binding at the beginning of each test case.
+module Bacon
+  class Context
+    alias _real_it it
+    def it(description, &block)
+      Pry.toplevel_binding = nil
+      _real_it(description, &block)
+    end
+  end
+end
+
 # A global space for storing temporary state during tests.
 Pad = OpenStruct.new
 def Pad.clear
@@ -269,7 +280,9 @@ class PryTester
     @pry = Pry.new(options)
 
     if context
-      @pry.binding_stack << Pry.binding_for(context)
+      target = Pry.binding_for(context)
+      @pry.binding_stack << target
+      @pry.inject_sticky_locals(target)
     end
 
     @pry.input_array << nil # TODO: shouldn't need this