diff --git a/spec/oga/xpath/compiler/axes/ancestor_or_self_spec.rb b/spec/oga/xpath/compiler/axes/ancestor_or_self_spec.rb
index f12672f..8c1b55a 100644
--- a/spec/oga/xpath/compiler/axes/ancestor_or_self_spec.rb
+++ b/spec/oga/xpath/compiler/axes/ancestor_or_self_spec.rb
@@ -1,38 +1,71 @@
 require 'spec_helper'
 
 describe Oga::XPath::Compiler do
-  describe 'ancestor-or-self axis' do
-    before do
-      @document = parse('<a><b><c></c></b></a>')
+  before do
+    @document = parse('<a foo="bar"><b><c></c></b></a>')
 
-      @a1 = @document.children[0]
-      @b1 = @a1.children[0]
-      @c1 = @b1.children[0]
+    @a1 = @document.children[0]
+    @b1 = @a1.children[0]
+    @c1 = @b1.children[0]
+  end
+
+  describe 'relative to a document' do
+    describe 'ancestor-or-self::a' do
+      it 'returns an empty NodeSet' do
+        evaluate_xpath(@document).should == node_set
+      end
+    end
+  end
+
+  describe 'relative to an attribute' do
+    describe 'ancestor-or-self::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@a1.attribute('foo')).should == node_set(@a1)
+      end
+    end
+  end
+
+  describe 'relative to an element' do
+    describe 'ancestor-or-self::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@a1)
+      end
     end
 
-    it 'returns a node set containing the direct ancestor' do
-      evaluate_xpath(@c1, 'ancestor-or-self::b').should == node_set(@b1)
+    describe 'ancestor-or-self::b' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@b1)
+      end
     end
 
-    it 'returns a node set containing a higher ancestor' do
-      evaluate_xpath(@c1, 'ancestor-or-self::a').should == node_set(@a1)
+    describe 'ancestor-or-self::c' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@c1)
+      end
     end
 
-    it 'returns a node set containing the context node itself' do
-      evaluate_xpath(@c1, 'ancestor-or-self::c').should == node_set(@c1)
+    describe 'ancestor-or-self::*[1]' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@c1)
+      end
     end
 
-    it 'returns a node set containing the first ancestor' do
-      evaluate_xpath(@c1, 'ancestor-or-self::*[1]').should == node_set(@c1)
+    describe 'ancestor-or-self::*' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@c1, @b1, @a1)
+      end
     end
 
-    it 'returns a node set containing all ancestors' do
-      evaluate_xpath(@c1, 'ancestor-or-self::*')
-        .should == node_set(@c1, @b1, @a1)
+    describe 'ancestor-or-self::foo' do
+      it 'returns an empty NodeSet' do
+        evaluate_xpath(@c1).should == node_set
+      end
     end
 
-    it 'returns an empty node set for non existing ancestors' do
-      evaluate_xpath(@c1, 'ancestor-or-self::foo').should == node_set
+    describe 'ancestor-or-self::*/ancestor-or-self::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@a1)
+      end
     end
   end
 end
diff --git a/spec/oga/xpath/compiler/axes/ancestor_spec.rb b/spec/oga/xpath/compiler/axes/ancestor_spec.rb
index 5772ba3..cd7d50b 100644
--- a/spec/oga/xpath/compiler/axes/ancestor_spec.rb
+++ b/spec/oga/xpath/compiler/axes/ancestor_spec.rb
@@ -1,33 +1,65 @@
 require 'spec_helper'
 
 describe Oga::XPath::Compiler do
-  describe 'ancestor axis' do
-    before do
-      @document = parse('<a><b><c></c></b></a>')
+  before do
+    @document = parse('<a foo="bar"><b><c></c></b></a>')
 
-      @a1 = @document.children[0]
-      @b1 = @a1.children[0]
-      @c1 = @b1.children[0]
+    @a1 = @document.children[0]
+    @b1 = @a1.children[0]
+    @c1 = @b1.children[0]
+  end
+
+  describe 'relative to a document' do
+    describe 'ancestor::a' do
+      it 'returns an empty NodeSet' do
+        evaluate_xpath(@document).should == node_set
+      end
+    end
+  end
+
+  describe 'relative to an attribute' do
+    describe 'ancestor-or-self::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@a1.attribute('foo')).should == node_set(@a1)
+      end
+    end
+  end
+
+  describe 'relative to an element' do
+    describe 'ancestor::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@a1)
+      end
     end
 
-    it 'returns a node set containing a direct ancestor' do
-      evaluate_xpath(@c1, 'ancestor::b').should == node_set(@b1)
+    describe 'ancestor::b' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@b1)
+      end
     end
 
-    it 'returns a node set containing a higher ancestor' do
-      evaluate_xpath(@c1, 'ancestor::a').should == node_set(@a1)
+    describe 'ancestor::*[1]' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@b1)
+      end
     end
 
-    it 'returns a node set containing the first ancestor' do
-      evaluate_xpath(@c1, 'ancestor::*[1]').should == node_set(@b1)
+    describe 'ancestor::*' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@b1, @a1)
+      end
     end
 
-    it 'returns a node set containing all ancestors' do
-      evaluate_xpath(@c1, 'ancestor::*').should == node_set(@b1, @a1)
+    describe 'ancestor::c' do
+      it 'returns an empty NodeSet' do
+        evaluate_xpath(@c1).should == node_set
+      end
     end
 
-    it 'returns an empty node set for non existing ancestors' do
-      evaluate_xpath(@c1, 'ancestor::c').should == node_set
+    describe 'ancestor::*/ancestor::a' do
+      it 'returns a NodeSet' do
+        evaluate_xpath(@c1).should == node_set(@a1)
+      end
     end
   end
 end
diff --git a/spec/support/evaluation_helpers.rb b/spec/support/evaluation_helpers.rb
index 6e7f7a8..5bcbb55 100644
--- a/spec/support/evaluation_helpers.rb
+++ b/spec/support/evaluation_helpers.rb
@@ -5,7 +5,7 @@ module Oga
     # @param [String] xpath
     # @return [Oga::XML::NodeSet]
     #
-    def evaluate_xpath(document, xpath)
+    def evaluate_xpath(document, xpath = self.class.description)
       ast      = parse_xpath(xpath)
       compiler = Oga::XPath::Compiler.new
       block    = compiler.compile(ast)
@@ -20,7 +20,7 @@ module Oga
     # @param [String] css
     # @return [Oga::XML::NodeSet]
     #
-    def evaluate_css(document, css)
+    def evaluate_css(document, css = self.class.description)
       ast      = parse_css(css)
       compiler = Oga::XPath::Compiler.new
       block    = compiler.compile(ast)