Test for bad event types

2 files changed, 10 insertions, 0 deletions

diff --git a/lib/ruby2d/window.rb b/lib/ruby2d/window.rb
index 9970861..377523b 100644
--- a/lib/ruby2d/window.rb
+++ b/lib/ruby2d/window.rb
@@ -123,6 +123,9 @@ module Ruby2D
     end
 
     def on(event, &proc)
+      unless @events.has_key? event
+        raise Error, "`#{event}` is not a valid event type"
+      end
       event_id = new_event_key
       @events[event][event_id] = proc
       EventDescriptor.new(event, event_id)
diff --git a/test/events_spec.rb b/test/events_spec.rb
index f0e5411..a5fa279 100644
--- a/test/events_spec.rb
+++ b/test/events_spec.rb
@@ -1,6 +1,13 @@
 require 'ruby2d'
 
 RSpec.describe Window do
+  describe 'on :bad_event' do
+    it "raises exception if a bad event type is given" do
+      window = Ruby2D::Window.new
+      expect { window.on(:bad_event) }.to raise_error(Ruby2D::Error)
+    end
+  end
+
   [:key, :key_down, :key_held, :key_up].each do |key_event_type|
     describe "on #{key_event_type}" do
       it "allows binding of event" do