Allow multiple StrongParametersMatchers to exist at once.

The provided RSpec example looks a bit contrived, but it corresponds to
this perfectly reasonable Minitest test case that was not working:

  class UserControllerTest < ActionController::TestCase
    should permit(:name).for(:create)
    should_not permit(:admin).for(:create)
  end

This instantiates two matchers at class load time, which resulted in the
second one overriding the double collection of the first one. Then when
the tests are executed, the first matcher would fail, because its double
is not listening to ActionController::Parameters#permit -- only the
second matcher's double collection gets activated.

This is fixed in Doublespeak by only creating one double collection per
class.

NEWS.md

@@ -1,5 +1,9 @@
 # HEAD
 
+### Bug fixes
+
+* Fix `permit` so that it can be used more than once in the same test.
+
 * Revert change to `validate_uniqueness_of` made in 2.6.0 so that it no longer
   provides default values for non-primary, non-nullable columns. This approach
   was causing test failures because it makes the assumption that none of these

lib/shoulda/matchers/action_controller/strong_parameters_matcher.rb

@@ -213,7 +213,7 @@ module Shoulda
 
         def set_double_collection
           @double_collection =
-            Doublespeak.register_double_collection(::ActionController::Parameters)
+            Doublespeak.double_collection_for(::ActionController::Parameters)
 
           @double_collection.register_stub(:require).to_return { |params| params }
           @double_collection.register_proxy(:permit)

lib/shoulda/matchers/doublespeak.rb

@@ -7,7 +7,7 @@ module Shoulda
       class << self
         extend Forwardable
 
-        def_delegators :world, :register_double_collection,
+        def_delegators :world, :double_collection_for,
           :with_doubles_activated
 
         def world

lib/shoulda/matchers/doublespeak/world.rb

@@ -3,10 +3,8 @@ module Shoulda
     module Doublespeak
       # @private
       class World
-        def register_double_collection(klass)
-          double_collection = DoubleCollection.new(klass)
-          double_collections_by_class[klass] = double_collection
-          double_collection
+        def double_collection_for(klass)
+          double_collections_by_class[klass] ||= DoubleCollection.new(klass)
         end
 
         def with_doubles_activated

lib/shoulda/matchers/independent/delegate_matcher.rb

@@ -251,7 +251,7 @@ module Shoulda
 
         def register_subject_double_collection
           double_collection =
-            Doublespeak.register_double_collection(subject.singleton_class)
+            Doublespeak.double_collection_for(subject.singleton_class)
           double_collection.register_stub(target_method).
             to_return(target_double)
 

spec/shoulda/matchers/action_controller/strong_parameters_matcher_spec.rb

@@ -25,6 +25,15 @@ describe Shoulda::Matchers::ActionController do
 
       expect(@controller).to permit(:name, :age).for(:create)
     end
+
+    it 'can be used more than once in the same test' do
+      controller_for_resource_with_strong_parameters(action: :create) do
+        params.require(:user).permit(:name)
+      end
+
+      expect(@controller).to permit(:name).for(:create)
+      expect(@controller).not_to permit(:admin).for(:create)
+    end
   end
 end
 

spec/shoulda/matchers/doublespeak/world_spec.rb

@@ -2,18 +2,19 @@ require 'spec_helper'
 
 module Shoulda::Matchers::Doublespeak
   describe World do
-    describe '#register_double_collection' do
-      it 'calls DoubleCollection.new with the given class' do
-        DoubleCollection.expects(:new).with(:klass)
+    describe '#double_collection_for' do
+      it 'calls DoubleCollection.new once with the given class' do
+        DoubleCollection.expects(:new).with(:klass).returns(:klass).once
         world = described_class.new
-        world.register_double_collection(:klass)
+        world.double_collection_for(:klass)
+        world.double_collection_for(:klass)
       end
 
-      it 'returns the newly created DoubleCollection' do
+      it 'returns the created DoubleCollection' do
         double_collection = Object.new
         DoubleCollection.stubs(:new).with(:klass).returns(double_collection)
         world = described_class.new
-        expect(world.register_double_collection(:klass)).to be double_collection
+        expect(world.double_collection_for(:klass)).to be double_collection
       end
     end
 
@@ -40,9 +41,9 @@ module Shoulda::Matchers::Doublespeak
         DoubleCollection.stubs(:new).
           with(:klass3).
           returns(double_collections[2])
-        world.register_double_collection(:klass1)
-        world.register_double_collection(:klass2)
-        world.register_double_collection(:klass3)
+        world.double_collection_for(:klass1)
+        world.double_collection_for(:klass2)
+        world.double_collection_for(:klass3)
 
         world.with_doubles_activated { block_called = true }
 
@@ -57,32 +58,13 @@ module Shoulda::Matchers::Doublespeak
         world = described_class.new
 
         DoubleCollection.stubs(:new).returns(double_collection)
-        world.register_double_collection(:klass)
+        world.double_collection_for(:klass)
 
         begin
           world.with_doubles_activated { raise 'error' }
         rescue RuntimeError
         end
       end
-
-      it 'does not allow multiple DoubleCollections to be registered that represent the same class' do
-        double_collections = [stub, stub]
-        sequence = sequence('with_doubles_activated')
-        double_collections[0].expects(:activate).never
-        double_collections[0].expects(:deactivate).never
-        double_collections[1].expects(:activate).in_sequence(sequence)
-        double_collections[1].expects(:deactivate).in_sequence(sequence)
-
-        world = described_class.new
-
-        DoubleCollection.stubs(:new).
-          returns(double_collections[0]).then.
-          returns(double_collections[1])
-        world.register_double_collection(:klass1)
-        world.register_double_collection(:klass1)
-
-        world.with_doubles_activated { }
-      end
     end
   end
 end

spec/shoulda/matchers/doublespeak_spec.rb

@@ -2,10 +2,10 @@ require 'spec_helper'
 
 module Shoulda::Matchers
   describe Doublespeak do
-    describe '.register_double_collection' do
+    describe '.double_collection_for' do
       it 'delegates to its world' do
-        Doublespeak.world.expects(:register_double_collection).with(:klass)
-        described_class.register_double_collection(:klass)
+        Doublespeak.world.expects(:double_collection_for).with(:klass)
+        described_class.double_collection_for(:klass)
       end
     end