Change Base#update to accept attributes

If the intent of Active Resource to be similar enough to Active Record
for its users to be able to intuit its interfaces, the absence of
`Base#update` can is a surprise.

Prior to this commit, the was an existent `Base#update` protected method
that handles issuing the `PUT` request. Its interface is more akin to
`Base#save`, in that it did not accept attributes.

This commit foists that method from being `protected` to be `public`. It
changes the interface to accept attributes. It retains the original
implementation when the `attributes` argument is omitted (for the sake
of backwards compatibility). When `attributes` are provided, forward
them to the `Base#update_attributes` method. Explicitly document the
interface that indicates that the only way for public callers to invoke
the method if with an `attributes` argument.

This commit also implements the `Base#update_attribute` method in terms
of the `Base#update_attributes` method.

Author: seanpdoyle

lib/active_resource/base.rb

@@ -1461,7 +1461,7 @@ def dup
     #   my_company.save # sends PUT /companies/1 (update)
     def save
       run_callbacks :save do
-        new? ? create : update
+        new? ? create : _update
       end
     end
 
@@ -1623,8 +1623,7 @@ def load(attributes, remove_root = false, persisted = false)
     # exception will be raised. If saving fails because the resource is
     # invalid then <tt>false</tt> will be returned.
     def update_attribute(name, value)
-      self.send("#{name}=".to_sym, value)
-      self.save
+      update_attributes(name => value)
     end
 
     # Updates this resource with all the attributes from the passed-in Hash
@@ -1641,6 +1640,22 @@ def update_attributes(attributes)
       load(attributes, false) && save
     end
 
+    ##
+    # :method: update
+    # :call-seq:
+    #     update(attributes)
+    #
+    # Equivalent to update_attributes(attributes).
+    def update(attributes = nil)
+      if attributes
+        update_attributes(attributes)
+      else
+        ActiveResource.deprecator.warn("Calling update without arguments is deprecated. Use save instead")
+
+        _update
+      end
+    end
+
     # For checking <tt>respond_to?</tt> without searching the attributes (which is faster).
     alias_method :respond_to_without_attributes?, :respond_to?
 
@@ -1684,7 +1699,7 @@ def connection(refresh = false)
       end
 
       # Update the resource on the remote service.
-      def update
+      def _update
         run_callbacks :update do
           connection.put(element_path(prefix_options), encode, self.class.headers).tap do |response|
             load_attributes_from_response(response)

lib/active_resource/singleton.rb

@@ -122,7 +122,7 @@ def destroy
 
     protected
       # Update the resource on the remote service
-      def update
+      def _update
         connection.put(singleton_path(prefix_options), encode, self.class.headers).tap do |response|
           load_attributes_from_response(response)
         end

test/cases/base_test.rb

@@ -1256,6 +1256,49 @@ def test_update_attributes_as_strings
     assert_equal "USA", addy.country
   end
 
+  def test_deprecates_caliing_update_without_arguments
+    ActiveResource::HttpMock.respond_to.put "/posts/1.json", @default_request_headers
+
+    post = Post.new({ id: 1 }, true)
+
+    assert_deprecated "", ActiveResource.deprecator do
+      post.update
+    end
+    assert_equal post.encode, ActiveResource::HttpMock.requests.last.body
+  end
+
+  def test_symbols_to_update
+    ActiveResource::HttpMock.respond_to.put "/posts/1.json", @default_request_headers
+
+    post = Post.new({ id: 1, title: "hello" }, true)
+
+    assert_changes -> { post.title }, from: "hello", to: "goodbye" do
+      post.update(title: "goodbye")
+    end
+    assert_equal post.encode, ActiveResource::HttpMock.requests.last.body
+  end
+
+  def test_strings_to_update
+    ActiveResource::HttpMock.respond_to.put "/posts/1.json", @default_request_headers
+
+    post = Post.new({ id: 1, title: "hello" }, true)
+
+    assert_changes -> { post.title }, from: "hello", to: "goodbye" do
+      post.update("title" => "goodbye")
+    end
+    assert_equal post.encode, ActiveResource::HttpMock.requests.last.body
+  end
+
+  def test_raises_error_from_failed_update
+    ActiveResource::HttpMock.respond_to.put "/posts/1.json", @default_request_headers, nil, 400
+
+    post = Post.new({ id: 1, title: "hello" }, true)
+
+    assert_raises ActiveResource::BadRequest do
+      post.update(title: "goodbye")
+    end
+    assert_equal post.encode, ActiveResource::HttpMock.requests.last.body
+  end
 
   #####
   # Mayhem and destruction