Fix subclasses not inheriting headers set in the superclass

lib/active_resource/connection.rb

@@ -211,7 +211,7 @@ def default_header
 
       # Builds headers for request to remote service.
       def build_request_headers(headers, http_method, uri)
-        authorization_header(http_method, uri).update(default_header).update(http_format_header(http_method)).update(headers)
+        authorization_header(http_method, uri).update(default_header).update(http_format_header(http_method)).update(headers.to_hash)
       end
 
       def response_auth_header

lib/active_resource/inheriting_hash.rb

@@ -11,5 +11,24 @@ def initialize(parent_hash = {})
     def [](key)
       super || @parent_hash[key]
     end
+
+    # Merges the flattened parent hash (if it's an InheritingHash)
+    # with ourself
+    def to_hash
+      @parent_hash.to_hash.merge(self)
+    end
+
+    # So we can see the merged object in IRB or the Rails console
+    def pretty_print(pp)
+      pp.pp_hash to_hash
+    end
+
+    def inspect
+      to_hash.inspect
+    end
+
+    def to_s
+      inspect
+    end
   end
 end

test/abstract_unit.rb

@@ -141,7 +141,7 @@ def setup_response
     mock.get    "/posts/1.json",                 {}, @post
     mock.get    "/posts/1/comments.json",        {}, @comments
     # products
-    mock.get "/products/1.json", {}, @product
+    mock.get "/products/1.json", { "Accept" => "application/json", "X-Inherited-Header" => "present" }, @product
     mock.get "/products/1/inventory.json", {}, @inventory
     # pets
     mock.get "/people/1/pets.json", {}, @pets

test/cases/authorization_test.rb

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "base64"
 require "abstract_unit"
 
 class AuthorizationTest < ActiveSupport::TestCase

test/cases/inheritence_test.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+
+require "fixtures/product"
+
+class InheritenceTest < ActiveSupport::TestCase
+  def test_sub_class_retains_ancestor_headers
+    ActiveResource::HttpMock.respond_to do |mock|
+      mock.get "/sub_products/1.json",
+               { "Accept" => "application/json", "X-Inherited-Header" => "present" },
+               { id: 1, name: "Sub Product" }.to_json,
+               200
+    end
+
+    sub_product = SubProduct.find(1)
+    assert_equal "SubProduct", sub_product.class.to_s
+  end
+end

test/cases/inheriting_hash_test.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class InheritingHashTest < ActiveSupport::TestCase
+  def setup
+    @parent = ActiveResource::InheritingHash.new({ override_me: "foo", parent_key: "parent_value" })
+    @child = ActiveResource::InheritingHash.new(@parent)
+    @child[:override_me] = "bar"
+    @child[:child_only] = "baz"
+  end
+
+  def test_child_key_overrides_parent_key
+    assert_equal "bar", @child[:override_me]
+  end
+
+  def test_parent_key_available_on_lookup
+    assert_equal "parent_value", @child[:parent_key]
+  end
+
+  def test_conversion_to_regular_hash_includes_parent_keys
+    hash = @child.to_hash
+
+    assert_equal 3, hash.keys.length
+    assert_equal "parent_value", hash[:parent_key]
+  end
+end

test/fixtures/product.rb

@@ -2,4 +2,10 @@
 
 class Product < ActiveResource::Base
   self.site = "http://37s.sunrise.i:3000"
+  # X-Inherited-Header is for testing that any subclasses
+  # include the headers of this class
+  self.headers["X-Inherited-Header"] = "present"
+end
+
+class SubProduct < Product
 end