Fix test warnings when doing rake {test,spec} or script/test

lib/jekyll/document.rb

@@ -366,11 +366,10 @@ module Jekyll
     #
     # Returns -1, 0, +1 or nil depending on whether this doc's path is less than,
     #   equal or greater than the other doc's path. See String#<=> for more details.
-    def <=>(anotherDocument)
-      cmp = data['date'] <=> anotherDocument.data['date']
-      if 0 == cmp
-        cmp = path <=> anotherDocument.path
-      end
+    def <=>(other)
+      return nil if !other.respond_to?(:data)
+      cmp = data['date'] <=> other.data['date']
+      cmp = path <=> other.path if cmp == 0
       cmp
     end
 

test/test_document.rb

@@ -328,7 +328,7 @@ class TestDocument < JekyllUnitTest
     end
 
     should "be output in the correct place" do
-      assert_equal true, File.file?(@dest_file)
+      assert File.file?(@dest_file)
     end
   end
 

test/test_site.rb

@@ -465,7 +465,7 @@ class TestSite < JekyllUnitTest
       end
 
       should "print profile table" do
-        @site.liquid_renderer.should_receive(:stats_table)
+        expect(@site.liquid_renderer).to receive(:stats_table)
         @site.process
       end
     end