enable/disable for memoization

README.md

@@ -61,6 +61,21 @@ To be symmetric, it's also possible to define one or more parameters through the
   end
 ```
 
+In case you would like to disable memoization (ie testing) you can disable Memo::It:
+
+```ruby
+  # enabled is default
+  Memo.enabled? # => true
+
+  # disable memoization globally
+  Memo.disable
+  Memo.enabled? # => false
+
+  # re-enable memoization
+  Memo.enable
+  Memo.enabled? # => true
+```
+
 ## Installation
 
 ### As a Gem

lib/memo/it.rb

@@ -1,5 +1,20 @@
 module Memo
   VERSION = '0.2.0'
+
+  @enabled = true
+
+  def self.enabled?
+    @enabled
+  end
+
+  def self.enable
+    @enabled = true
+  end
+
+  def self.disable
+    @enabled = false
+  end
+
   module It
     def memo(only: [], ignore: [], &block)
       only = Array(only)
@@ -16,7 +31,7 @@ def memo(only: [], ignore: [], &block)
       keys = keys.flatten.map(&:to_s)
 
       @_memo_it ||= {}
-      return @_memo_it[keys] if @_memo_it.key? keys
+      return @_memo_it[keys] if Memo.enabled? && @_memo_it.key?(keys)
       @_memo_it[keys] = yield
     end
   end

test/memo/it_test.rb

@@ -6,6 +6,23 @@ def setup
       @mock = MiniTest::Mock.new
     end
 
+    def test_disabling
+      assert Memo.enabled?
+      Memo.disable
+      refute Memo.enabled?
+    ensure
+      Memo.enable
+    end
+
+    def test_no_memoization_when_disabled
+      Memo.disable
+      10.times { @mock.expect(:slow, :stuff) }
+      10.times { assert memo_without_parameters == :stuff }
+      @mock.verify
+    ensure
+      Memo.enable
+    end
+
     def test_memoizes_stuff
       @mock.expect(:slow, :stuff)
       10.times { assert memo_without_parameters == :stuff }