#459 - Fix iteration for genomics API which only has 1 item per page

lib/google/apis/core/base_service.rb

@@ -64,11 +64,16 @@ module Google
           loop do
             @last_result = @fetch_proc.call(page_token)
             items = @last_result.send(@items_field)
-            for item in items
-              item_count = item_count + 1
-              break if @max && item_count > @max
-              yield item
-            end unless items.nil?
+            if items.kind_of?(Array)
+              for item in items
+                item_count = item_count + 1
+                break if @max && item_count > @max
+                yield item
+              end
+            elsif items
+              # yield singular non-nil items (for genomics API)
+              yield items
+            end
             break if @max && item_count >= @max
             break if @last_result.next_page_token.nil? || @last_result.next_page_token == page_token
             page_token = @last_result.next_page_token

spec/google/apis/core/service_spec.rb

@@ -248,9 +248,9 @@ EOF
     context 'with fetch_all' do
       let(:responses) do
         data = {}
-        data[nil] = OpenStruct.new(next_page_token: 'p1', items: ['a', 'b', 'c'], alt_items: [1, 2 , 3])
-        data['p1'] = OpenStruct.new(next_page_token: 'p2', items: ['d', 'e', 'f'], alt_items: [4, 5, 6])
-        data['p2'] = OpenStruct.new(next_page_token: nil, items: ['g', 'h', 'i'], alt_items: [7,8, 9])
+        data[nil] = OpenStruct.new(next_page_token: 'p1', items: ['a', 'b', 'c'], alt_items: [1, 2 , 3], singular: 'foo')
+        data['p1'] = OpenStruct.new(next_page_token: 'p2', items: ['d', 'e', 'f'], alt_items: [4, 5, 6], singular: 'bar')
+        data['p2'] = OpenStruct.new(next_page_token: nil, items: ['g', 'h', 'i'], alt_items: [7,8, 9], singular: 'baz')
         data
       end
 
@@ -274,6 +274,10 @@ EOF
         expect(service.fetch_all(items: :alt_items) { |token| responses[token] } ).to contain_exactly(1, 2, 3, 4, 5, 6, 7, 8, 9)
       end
 
+      it 'should allow iterating over singular items' do
+        expect(service.fetch_all(items: :singular) { |token| responses[token] } ).to contain_exactly('foo', 'bar', 'baz')
+      end
+
       it 'should allow limiting the number of items to fetch' do
         expect(service.fetch_all(max: 5) { |token| responses[token] } ).to contain_exactly('a', 'b', 'c', 'd', 'e')
       end