Revamped compiler "preceding-sibling" specs

lib/oga/xpath/compiler.rb

@@ -387,6 +387,7 @@ module Oga
               .else    { parent.assign(self.nil) }
           end
           .followed_by do
+            document_or_node(root).if_true do
               root.each_node.add_block(doc_node) do
                 doc_node.eq(input)
                   .if_true { self.break }
@@ -398,6 +399,7 @@ module Oga
               end
             end
           end
+      end
 
       # @param [AST::Node] ast
       # @param [Oga::Ruby::Node] input

spec/oga/xpath/compiler/axes/preceding_sibling_spec.rb

@@ -1,10 +1,9 @@
 require 'spec_helper'
 
 describe Oga::XPath::Compiler do
-  describe 'preceding-sibling axis' do
   before do
-      @document = parse(<<-EOF.strip.gsub(/\s+/m, ''))
-<root>
+    @document = parse(<<-EOF.strip.gsub(/^\s+|\n/m, ''))
+<root foo="bar">
   <foo>
   </foo>
   <bar>
@@ -19,18 +18,41 @@ describe Oga::XPath::Compiler do
     @bar1 = @document.children[0].children[1]
   end
 
-    it 'returns a node set containing preceding siblings of root/bar' do
-      evaluate_xpath(@document, 'root/bar/preceding-sibling::foo')
-        .should == node_set(@foo1)
+  describe 'relative to a document' do
+    describe 'preceding-sibling::*' do
+      it 'returns an empty NodeSet' do
+        evaluate_xpath(@document).should == node_set
+      end
     end
 
-    it 'returns a node set containing preceding siblings of root/bar/baz' do
-      evaluate_xpath(@document, 'root/bar/baz/preceding-sibling::foo')
-        .should == node_set(@foo2)
+    describe 'root/bar/preceding-sibling::foo' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@document).should == node_set(@foo1)
+      end
     end
 
-    it 'returns a node set containing preceding siblings relative to root/bar' do
-      evaluate_xpath(@bar1, 'preceding-sibling::foo').should == node_set(@foo1)
+    describe 'root/bar/baz/preceding-sibling::foo' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@document).should == node_set(@foo2)
+      end
+    end
+  end
+
+  describe 'relative to an element' do
+    describe 'preceding-sibling::foo' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@bar1).should == node_set(@foo1)
+      end
+    end
+  end
+
+  describe 'relative to an attribute' do
+    describe 'preceding-sibling::*' do
+      it 'returns an empty NodeSet' do
+        root = @document.children[0]
+
+        evaluate_xpath(root.attribute('foo')).should == node_set
+      end
     end
   end
 end