Correctly handle false single values.

The use of the #one? method was causing a boolean value of false to be
skipped.  This is unexpected and problematic in most situations.

lib/jbuilder.rb

@@ -126,7 +126,7 @@ def method_missing(method, *args)
 
       # json.age 32
       # { "age": 32 }
-      when args.one?
+      when args.length == 1
         set! method, args.first
 
       # json.comments { |json| ... }
@@ -182,4 +182,4 @@ def _inline_extract(container, record, attributes)
     end
 end
 
-require "jbuilder_template" if defined?(ActionView::Template)
+require "jbuilder_template" if defined?(ActionView::Template)

test/jbuilder_test.rb

@@ -12,6 +12,14 @@ class JbuilderTest < ActiveSupport::TestCase
     assert_equal "hello", JSON.parse(json)["content"]
   end
 
+  test "single key with false value" do
+    json = Jbuilder.encode do |json|
+      json.content false
+    end
+
+    assert_equal false, JSON.parse(json)["content"]
+  end
+
   test "multiple keys" do
     json = Jbuilder.encode do |json|
       json.title "hello"
@@ -225,4 +233,4 @@ def initialize(name, age)
 
     assert_equal "stuff", JSON.parse(json)["each"]
   end
-end
+end