3 files changed, 111 insertions, 2 deletions
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
new file mode 100644
index 0000000000..402caf21f7
--- /dev/null
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -0,0 +1,107 @@
+require "cases/helper"
+require "active_support/hash_with_indifferent_access"
+
+class AttributeAssignmentTest < ActiveModel::TestCase
+  class Model
+    include ActiveModel::AttributeAssignment
+
+    attr_accessor :name, :description
+
+    def initialize(attributes = {})
+      assign_attributes(attributes)
+    end
+
+    def broken_attribute=(value)
+      raise ErrorFromAttributeWriter
+    end
+
+    protected
+
+    attr_writer :metadata
+  end
+
+  class ErrorFromAttributeWriter < StandardError
+  end
+
+  class ProtectedParams < ActiveSupport::HashWithIndifferentAccess
+    def permit!
+      @permitted = true
+    end
+
+    def permitted?
+      @permitted ||= false
+    end
+
+    def dup
+      super.tap do |duplicate|
+        duplicate.instance_variable_set :@permitted, permitted?
+      end
+    end
+  end
+
+  test "simple assignment" do
+    model = Model.new
+
+    model.assign_attributes(name: "hello", description: "world")
+    assert_equal "hello", model.name
+    assert_equal "world", model.description
+  end
+
+  test "assign non-existing attribute" do
+    model = Model.new
+    error = assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+      model.assign_attributes(hz: 1)
+    end
+
+    assert_equal model, error.record
+    assert_equal "hz", error.attribute
+  end
+
+  test "assign private attribute" do
+    model = Model.new
+    assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+      model.assign_attributes(metadata: { a: 1 })
+    end
+  end
+
+  test "does not swallow errors raised in an attribute writer" do
+    assert_raises(ErrorFromAttributeWriter) do
+      Model.new(broken_attribute: 1)
+    end
+  end
+
+  test "an ArgumentError is raised if a non-hash-like obejct is passed" do
+    assert_raises(ArgumentError) do
+      Model.new(1)
+    end
+  end
+
+  test "forbidden attributes cannot be used for mass assignment" do
+    params = ProtectedParams.new(name: "Guille", description: "m")
+
+    assert_raises(ActiveModel::ForbiddenAttributesError) do
+      Model.new(params)
+    end
+  end
+
+  test "permitted attributes can be used for mass assignment" do
+    params = ProtectedParams.new(name: "Guille", description: "desc")
+    params.permit!
+    model = Model.new(params)
+
+    assert_equal "Guille", model.name
+    assert_equal "desc", model.description
+  end
+
+  test "regular hash should still be used for mass assignment" do
+    model = Model.new(name: "Guille", description: "m")
+
+    assert_equal "Guille", model.name
+    assert_equal "m", model.description
+  end
+
+  test "assigning no attributes should not raise, even if the hash is un-permitted" do
+    model = Model.new
+    assert_nil model.assign_attributes(ProtectedParams.new({}))
+  end
+end
diff --git a/activemodel/test/cases/errors_test.rb b/activemodel/test/cases/errors_test.rb
index 9cfba9812b..17dbb817d0 100644
--- a/activemodel/test/cases/errors_test.rb
+++ b/activemodel/test/cases/errors_test.rb
@@ -347,7 +347,7 @@ class ErrorsTest < ActiveModel::TestCase
     errors.add(:name, :invalid)
     errors_dup = errors.dup
     errors_dup.add(:name, :taken)
-    assert_not_same errors_dup.details, errors.details
+    assert_not_equal errors_dup.details, errors.details
   end
 
   test "delete removes details on given attribute" do
diff --git a/activemodel/test/cases/model_test.rb b/activemodel/test/cases/model_test.rb
index ee0fa26546..9a8d873ec9 100644
--- a/activemodel/test/cases/model_test.rb
+++ b/activemodel/test/cases/model_test.rb
@@ -70,6 +70,8 @@ class ModelTest < ActiveModel::TestCase
   end
 
   def test_mixin_initializer_when_args_dont_exist
-    assert_raises(NoMethodError) { SimpleModel.new(hello: 'world') }
+    assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+      SimpleModel.new(hello: 'world')
+    end
   end
 end