diff --git a/lib/oga/xpath/compiler.rb b/lib/oga/xpath/compiler.rb
index f4d6eab..f1ef376 100644
--- a/lib/oga/xpath/compiler.rb
+++ b/lib/oga/xpath/compiler.rb
@@ -714,8 +714,10 @@ module Oga
             needle_lit.assign(try_match_first_node(needle, input))
           end
           .followed_by do
-            conversion.to_string(haystack_lit)
+            converted = conversion.to_string(haystack_lit)
               .include?(conversion.to_string(needle_lit))
+
+            block_given? ? converted.if_true { yield } : converted
           end
       end
 
@@ -961,11 +963,7 @@ module Oga
             converted = conversion.to_string(haystack_var)
               .start_with?(conversion.to_string(needle_var))
 
-            if block_given?
-              converted.if_true { yield }
-            else
-              converted
-            end
+            block_given? ? converted.if_true { yield } : converted
           end
       end
 
diff --git a/spec/oga/xpath/compiler/calls/contains_spec.rb b/spec/oga/xpath/compiler/calls/contains_spec.rb
index 4dd2eaa..7c94242 100644
--- a/spec/oga/xpath/compiler/calls/contains_spec.rb
+++ b/spec/oga/xpath/compiler/calls/contains_spec.rb
@@ -4,34 +4,45 @@ describe Oga::XPath::Compiler do
   describe 'contains() function' do
     before do
       @document = parse('<root><a>foo</a><b>foobar</b></root>')
+
+      @a1 = @document.children[0].children[0]
     end
 
-    it 'returns true if the 1st string contains the 2nd string' do
-      evaluate_xpath(@document, 'contains("foobar", "oo")').should == true
+    describe 'at the top-level' do
+      it 'returns true if the 1st string contains the 2nd string' do
+        evaluate_xpath(@document, 'contains("foobar", "oo")').should == true
+      end
+
+      it "returns false if the 1st string doesn't contain the 2nd string" do
+        evaluate_xpath(@document, 'contains("foobar", "baz")').should == false
+      end
+
+      it 'returns true if the 1st node set contains the 2nd string' do
+        evaluate_xpath(@document, 'contains(root/a, "oo")').should == true
+      end
+
+      it 'returns true if the 1st node set contains the 2nd node set' do
+        evaluate_xpath(@document, 'contains(root/b, root/a)').should == true
+      end
+
+      it "returns false if the 1st node doesn't contain the 2nd node set" do
+        evaluate_xpath(@document, 'contains(root/a, root/b)').should == false
+      end
+
+      it 'returns true if the 1st string contains the 2nd node set' do
+        evaluate_xpath(@document, 'contains("foobar", root/a)').should == true
+      end
+
+      it 'returns true when using two empty strings' do
+        evaluate_xpath(@document, 'contains("", "")').should == true
+      end
     end
 
-    it "returns false if the 1st string doesn't contain the 2nd string" do
-      evaluate_xpath(@document, 'contains("foobar", "baz")').should == false
-    end
-
-    it 'returns true if the 1st node set contains the 2nd string' do
-      evaluate_xpath(@document, 'contains(root/a, "oo")').should == true
-    end
-
-    it 'returns true if the 1st node set contains the 2nd node set' do
-      evaluate_xpath(@document, 'contains(root/b, root/a)').should == true
-    end
-
-    it "returns false if the 1st node doesn't contain the 2nd node set" do
-      evaluate_xpath(@document, 'contains(root/a, root/b)').should == false
-    end
-
-    it 'returns true if the 1st string contains the 2nd node set' do
-      evaluate_xpath(@document, 'contains("foobar", root/a)').should == true
-    end
-
-    it 'returns true when using two empty strings' do
-      evaluate_xpath(@document, 'contains("", "")').should == true
+    describe 'in a predicate' do
+      it 'returns a NodeSet containing all matching nodes' do
+        evaluate_xpath(@document, 'root/a[contains("foo", "foo")]')
+          .should == node_set(@a1)
+      end
     end
   end
 end
diff --git a/spec/oga/xpath/compiler/calls/starts_with_spec.rb b/spec/oga/xpath/compiler/calls/starts_with_spec.rb
index c2c6310..4c9e9a4 100644
--- a/spec/oga/xpath/compiler/calls/starts_with_spec.rb
+++ b/spec/oga/xpath/compiler/calls/starts_with_spec.rb
@@ -4,34 +4,45 @@ describe Oga::XPath::Compiler do
   describe 'starts-with() function' do
     before do
       @document = parse('<root><a>foo</a><b>foobar</b></root>')
+
+      @a1 = @document.children[0].children[0]
     end
 
-    it 'returns true if the 1st string starts with the 2nd string' do
-      evaluate_xpath(@document, 'starts-with("foobar", "foo")').should == true
+    describe 'at the top-level' do
+      it 'returns true if the 1st string starts with the 2nd string' do
+        evaluate_xpath(@document, 'starts-with("foobar", "foo")').should == true
+      end
+
+      it "returns false if the 1st string doesn't start with the 2nd string" do
+        evaluate_xpath(@document, 'starts-with("foobar", "baz")').should == false
+      end
+
+      it 'returns true if the 1st node set starts with the 2nd string' do
+        evaluate_xpath(@document, 'starts-with(root/a, "foo")').should == true
+      end
+
+      it 'returns true if the 1st node set starts with the 2nd node set' do
+        evaluate_xpath(@document, 'starts-with(root/b, root/a)').should == true
+      end
+
+      it "returns false if the 1st node set doesn't start with the 2nd string" do
+        evaluate_xpath(@document, 'starts-with(root/a, "baz")').should == false
+      end
+
+      it 'returns true if the 1st string starts with the 2nd node set' do
+        evaluate_xpath(@document, 'starts-with("foobar", root/a)').should == true
+      end
+
+      it 'returns true when using two empty strings' do
+        evaluate_xpath(@document, 'starts-with("", "")').should == true
+      end
     end
 
-    it "returns false if the 1st string doesn't start with the 2nd string" do
-      evaluate_xpath(@document, 'starts-with("foobar", "baz")').should == false
-    end
-
-    it 'returns true if the 1st node set starts with the 2nd string' do
-      evaluate_xpath(@document, 'starts-with(root/a, "foo")').should == true
-    end
-
-    it 'returns true if the 1st node set starts with the 2nd node set' do
-      evaluate_xpath(@document, 'starts-with(root/b, root/a)').should == true
-    end
-
-    it "returns false if the 1st node set doesn't start with the 2nd string" do
-      evaluate_xpath(@document, 'starts-with(root/a, "baz")').should == false
-    end
-
-    it 'returns true if the 1st string starts with the 2nd node set' do
-      evaluate_xpath(@document, 'starts-with("foobar", root/a)').should == true
-    end
-
-    it 'returns true when using two empty strings' do
-      evaluate_xpath(@document, 'starts-with("", "")').should == true
+    describe 'in a predicate' do
+      it 'returns a NodeSet containing all matching nodes' do
+        evaluate_xpath(@document, 'root/a[starts-with("foo", "foo")]')
+          .should == node_set(@a1)
+      end
     end
   end
 end