test files renamed with test_ prefix

error tests added

Rakefile updated with new test file names

event tasks moved into :e namespace

Rakefile

@@ -5,19 +5,25 @@ HERE = __dir__
 Minitest::TestTask.create(:test) do |t|
   t.libs << "test"
   t.warning = false
-  t.test_globs = ["test/**/*_test.rb"]
+  t.test_globs = ["test/**/test_*.rb"]
 end
 
 task default: :test
-task :events do
-  filepath = File.join(HERE, "examples", "events", "main.rb")
-  ruby filepath
-end
-task :levels do
-  filepath = File.join(HERE, "examples", "levels", "main.rb")
-  ruby filepath
-end
-task :scene_rotate do
-  filepath = File.join(HERE, "examples", "scene_rotate", "main.rb")
-  ruby filepath
+
+namespace :e do
+  desc "Runs the events example"
+  task :events do
+    filepath = File.join(HERE, "examples", "events", "main.rb")
+    ruby filepath
+  end
+  desc "Runs the levels example"
+  task :levels do
+    filepath = File.join(HERE, "examples", "levels", "main.rb")
+    ruby filepath
+  end
+  desc "Runs the scene_rotate example"
+  task :scene_rotate do
+    filepath = File.join(HERE, "examples", "scene_rotate", "main.rb")
+    ruby filepath
+  end
 end