Added Dash and Trash#update_attributes.

4 files changed, 72 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3b29de6..dbacf49 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 
 **Note:** This version introduces several backward incompatible API changes. See [UPGRADING](UPGRADING.md) for details.
 
+* [#172](https://github.com/intridea/hashie/pull/172): Added Dash and Trash#update_attributes - [@gregory](https://github.com/gregory).
 * [#169](https://github.com/intridea/hashie/pull/169): Hash#to_hash will also convert nested objects that implement to_hash - [@gregory](https://github.com/gregory).
 * [#150](https://github.com/intridea/hashie/pull/159): Handle nil intermediate object on deep fetch - [@stephenaument](https://github.com/stephenaument).
 * [#146](https://github.com/intridea/hashie/issues/146): Mash#respond_to? inconsistent with #method_missing and does not respond to #permitted? - [@dblock](https://github.com/dblock).
diff --git a/README.md b/README.md
index 69cbaee..745dc51 100644
--- a/README.md
+++ b/README.md
@@ -205,6 +205,11 @@ p.occupation   # => 'Rubyist'
 p.email        # => 'abc@def.com'
 p[:awesome]    # => NoMethodError
 p[:occupation] # => 'Rubyist'
+p.update_attributes(name: 'Trudy', occupation: 'Evil')
+p.occupation   # => 'Evil'
+p.name         # => 'Trudy'
+p.update_attributes(occupation: nil)
+p.occupation   # => 'Rubyist'
 ```
 
 Properties defined as symbols are not the same thing as properties defined as strings.
diff --git a/lib/hashie/dash.rb b/lib/hashie/dash.rb
index 941e566..5a26861 100644
--- a/lib/hashie/dash.rb
+++ b/lib/hashie/dash.rb
@@ -91,7 +91,7 @@ module Hashie
       end
 
       initialize_attributes(attributes)
-      assert_required_properties_set!
+      assert_required_attributes_set!
     end
 
     alias_method :_regular_reader, :[]
@@ -142,6 +142,19 @@ module Hashie
       self
     end
 
+    def update_attributes!(attributes)
+      initialize_attributes(attributes)
+
+      self.class.defaults.each_pair do |prop, value|
+        self[prop] = begin
+          value.dup
+        rescue TypeError
+          value
+        end if self[prop].nil?
+      end
+      assert_required_attributes_set!
+    end
+
     private
 
     def initialize_attributes(attributes)
@@ -156,7 +169,7 @@ module Hashie
       end
     end
 
-    def assert_required_properties_set!
+    def assert_required_attributes_set!
       self.class.required_properties.each do |required_property|
         assert_property_set!(required_property)
       end
diff --git a/spec/hashie/dash_spec.rb b/spec/hashie/dash_spec.rb
index 04ce0aa..6b10a52 100644
--- a/spec/hashie/dash_spec.rb
+++ b/spec/hashie/dash_spec.rb
@@ -18,6 +18,14 @@ class DashNoRequiredTest < Hashie::Dash
   property :count, default: 0
 end
 
+class DashWithCoercion < Hashie::Dash
+  include Hashie::Extensions::Coercion
+  property :person
+  property :city
+
+  coerce_key :person, ::DashNoRequiredTest
+end
+
 class PropertyBangTest < Hashie::Dash
   property :important!
 end
@@ -266,6 +274,49 @@ describe DashTest do
       end
     end
   end
+
+  describe '#update_attributes!(params)' do
+    let(:params) { { first_name: 'Alice', email: 'alice@example.com' } }
+
+    context 'when there is coercion' do
+      let(:params_before) { { city: 'nyc', person: { first_name: 'Bob', email: 'bob@example.com' } } }
+      let(:params_after) { { city: 'sfo', person: { first_name: 'Alice', email: 'alice@example.com' } } }
+
+      subject { DashWithCoercion.new(params_before) }
+
+      it 'update the attributes' do
+        expect(subject.person.first_name).to eq params_before[:person][:first_name]
+        subject.update_attributes!(params_after)
+        expect(subject.person.first_name).to eq params_after[:person][:first_name]
+      end
+    end
+
+    it 'update the attributes' do
+      subject.update_attributes!(params)
+      expect(subject.first_name).to eq params[:first_name]
+      expect(subject.email).to eq params[:email]
+      expect(subject.count).to eq subject.class.defaults[:count]
+    end
+
+    context 'when required property is update to nil' do
+      let(:params) { { first_name: nil, email: 'alice@example.com' } }
+
+      it 'raise an ArgumentError' do
+        expect { subject.update_attributes!(params) }.to raise_error(ArgumentError)
+      end
+    end
+
+    context 'when a default property is update to nil' do
+      let(:params) { { count: nil, email: 'alice@example.com' } }
+
+      it 'set the property back to the default value' do
+        subject.update_attributes!(params)
+        expect(subject.email).to eq params[:email]
+        expect(subject.count).to eq subject.class.defaults[:count]
+      end
+    end
+  end
+
 end
 
 describe Hashie::Dash, 'inheritance' do