3 files changed, 30 insertions, 3 deletions
diff --git a/activemodel/test/cases/observing_test.rb b/activemodel/test/cases/observing_test.rb
index f6ec24ae57..1a80b5d854 100644
--- a/activemodel/test/cases/observing_test.rb
+++ b/activemodel/test/cases/observing_test.rb
@@ -70,10 +70,25 @@ class ObservingTest < ActiveModel::TestCase
     ObservedModel.instantiate_observers
   end
 
+  test "raises an appropriate error when a developer accidentally adds the wrong class (i.e. Widget instead of WidgetObserver)" do
+    assert_raise ArgumentError do
+      ObservedModel.observers = ['string']
+      ObservedModel.instantiate_observers
+    end
+    assert_raise ArgumentError do
+      ObservedModel.observers = [:string]
+      ObservedModel.instantiate_observers
+    end
+    assert_raise ArgumentError do
+      ObservedModel.observers = [String]
+      ObservedModel.instantiate_observers
+    end
+  end
+
   test "passes observers to subclasses" do
     FooObserver.instance
     bar = Class.new(Foo)
-    assert_equal Foo.count_observers, bar.count_observers
+    assert_equal Foo.observers_count, bar.observers_count
   end
 end
 
diff --git a/activemodel/test/cases/secure_password_test.rb b/activemodel/test/cases/secure_password_test.rb
index 4338a3fc53..c451cc1aca 100644
--- a/activemodel/test/cases/secure_password_test.rb
+++ b/activemodel/test/cases/secure_password_test.rb
@@ -19,6 +19,12 @@ class SecurePasswordTest < ActiveModel::TestCase
     assert !@user.valid?, 'user should be invalid'
   end
 
+  test "blank password doesn't override previous password" do
+    @user.password = 'test'
+    @user.password = ''
+    assert_equal @user.password, 'test'
+  end
+
   test "password must be present" do
     assert !@user.valid?
     assert_equal 1, @user.errors.size
diff --git a/activemodel/test/cases/translation_test.rb b/activemodel/test/cases/translation_test.rb
index 54e86d48db..4999583802 100644
--- a/activemodel/test/cases/translation_test.rb
+++ b/activemodel/test/cases/translation_test.rb
@@ -82,9 +82,15 @@ class ActiveModelI18nTests < ActiveModel::TestCase
   end
 
   def test_human_does_not_modify_options
-    options = {:default => 'person model'}
+    options = { :default => 'person model' }
     Person.model_name.human(options)
-    assert_equal({:default => 'person model'}, options)
+    assert_equal({ :default => 'person model' }, options)
+  end
+
+  def test_human_attribute_name_does_not_modify_options
+    options = { :default => 'Cool gender' }
+    Person.human_attribute_name('gender', options)
+    assert_equal({ :default => 'Cool gender' }, options)
   end
 end