diff --git a/persistent-data/buffer.h b/persistent-data/buffer.h
index 5f35cd8..45e2390 100644
--- a/persistent-data/buffer.h
+++ b/persistent-data/buffer.h
@@ -32,19 +32,19 @@
 //----------------------------------------------------------------
 
 namespace persistent_data {
-	// Joe has buffer<> in other parts of the code, so...
 	uint32_t const DEFAULT_BUFFER_SIZE = 4096;
 
 	// Allocate buffer of Size with Alignment imposed.
 	//
-	// Allocation needs to be on the heap in order to provide alignment guarantees!
-	// 
+	// Allocation needs to be on the heap in order to provide alignment
+	// guarantees.
+	//
 	// Alignment must be a power of two.
-
 	template <uint32_t Size = DEFAULT_BUFFER_SIZE, uint32_t Alignment = 512>
 	class buffer : private boost::noncopyable {
 	public:
 		typedef boost::shared_ptr<buffer> ptr;
+		typedef boost::shared_ptr<buffer const> const_ptr;
 
 		unsigned char &operator[](unsigned index) {
 			check_index(index);
diff --git a/unit-tests/buffer_t.cc b/unit-tests/buffer_t.cc
index 248ad0a..a5d98a5 100644
--- a/unit-tests/buffer_t.cc
+++ b/unit-tests/buffer_t.cc
@@ -82,12 +82,20 @@ BOOST_AUTO_TEST_CASE(buffer_8_a_8_access)
 	BOOST_CHECK_EQUAL((*b)[0], '\0');
 }
 
+BOOST_AUTO_TEST_CASE(buffer_8_a_8_oob)
+{
+	uint32_t const sz = 8, align = 8;
+	buffer<sz, align>::ptr b = create_buffer<sz, align>();
+
+	BOOST_CHECK_NO_THROW((*b)[8] = 0);
+}
+
 BOOST_AUTO_TEST_CASE(buffer_8_a_8_const_access)
 {
 	uint32_t const sz = 8, align = 8;
-	buffer<sz, align>::ptr const b = create_buffer<sz, align>();
+	buffer<sz, align>::const_ptr b = create_buffer<sz, align>();
 
-	(*b)[0] = 0; // Compile time error accessing read-only location 
+	// (*b)[0] = 0; // Compile time error accessing read-only location 
 }
 
 // 8 byte buffer size, varying alignment from 1 - 7