Add chain :matching

lib/n_plus_one_control/rspec/matchers/perform_linear_number_of_queries.rb

@@ -8,6 +8,10 @@
     @factors = factors
   end
 
+  chain :matching do |pattern|
+    @pattern = pattern
+  end
+
   chain :with_warming_up do
     @warmup = true
   end

spec/n_plus_one_control/rspec/matchers/perform_linear_number_of_queries_spec.rb

@@ -60,6 +60,30 @@
       end
     end
 
+    context "with matching", :n_plus_one do
+      populate { |n| create_list(:post, n) }
+
+      specify do
+        expect { Post.find_each { |p| p.user.name } }
+          .to perform_linear_number_of_queries.matching(/users/)
+      end
+
+      context "with matching is provided globally", :n_plus_one do
+        around(:each) do |ex|
+          NPlusOneControl.default_matching = "users"
+          ex.run
+          NPlusOneControl.default_matching = nil
+        end
+
+        populate { |n| create_list(:post, n) }
+
+        specify do
+          expect { Post.find_each { |p| p.user.name } }
+            .to perform_linear_number_of_queries
+        end
+      end
+    end
+
     context "with warming up", :n_plus_one do
       let(:cache) { double "cache" }