Merge pull request #32 from jvanbaarsen/add-group-exists

Add a method to check in clean way if group exists

lib/flipper.rb

@@ -37,6 +37,13 @@ def self.unregister_groups
     groups.clear
   end
 
+  # Public: Check if a group exists
+  #
+  # Returns boolean
+  def self.group_exists?(name)
+    self.groups.key?(name)
+  end
+
   # Internal: Fetches a group by name.
   #
   # name - The Symbol name of the group.

lib/flipper/registry.rb

@@ -45,14 +45,20 @@ def add(key, value)
 
     def get(key)
       key = key.to_sym
-
       @mutex.synchronize {
         @source.fetch(key) {
           raise KeyNotFound.new(key)
         }
       }
     end
 
+    def key?(key)
+      key = key.to_sym
+      @mutex.synchronize {
+        @source.has_key?(key)
+      }
+    end
+
     def each(&block)
       @mutex.synchronize { @source.dup }.each(&block)
     end

spec/flipper/registry_spec.rb

@@ -52,6 +52,20 @@
     end
   end
 
+  describe "#key?" do
+    before do
+      source[:admins] = "admins"
+    end
+
+    it "returns true if the key exists" do
+      subject.key?(:admins).should eq true
+    end
+
+    it "returns false if the key does not exists" do
+      subject.key?(:unknown_key).should eq false
+    end
+  end
+
   describe "#each" do
     before do
       source[:admins] = 'admins'

spec/flipper_spec.rb

@@ -8,6 +8,19 @@
     end
   end
 
+  describe ".group_exists" do
+    it "returns true if the group is already created" do
+      group = Flipper.register('admins') { |actor| actor.admin? }
+      Flipper.group_exists?(:admins).should eq(true)
+    end
+
+    it "returns false when the group is not yet registered" do
+      registry = Flipper::Registry.new
+      Flipper.groups = registry
+      Flipper.group_exists?(:non_existing).should eq(false)
+    end
+  end
+
   describe ".groups" do
     it "returns a registry instance" do
       Flipper.groups.should be_instance_of(Flipper::Registry)