diff --git a/libs/acn/PDU.cpp b/libs/acn/PDU.cpp
index 0f256eca1..33e40f720 100644
--- a/libs/acn/PDU.cpp
+++ b/libs/acn/PDU.cpp
@@ -50,6 +50,16 @@ unsigned int PDU::Size() const {
  * @return false on error, true otherwise
  */
 bool PDU::Pack(uint8_t *buffer, unsigned int *length) const {
+  if (!buffer) {
+    OLA_WARN << "PDU::Pack: missing buffer";
+    return false;
+  }
+
+  if (!length) {
+    OLA_WARN << "PDU::Pack: missing length";
+    return false;
+  }
+
   unsigned int size = Size();
   unsigned int offset = 0;
 
diff --git a/libs/acn/PDU.h b/libs/acn/PDU.h
index 2be285dea..531a8e96b 100644
--- a/libs/acn/PDU.h
+++ b/libs/acn/PDU.h
@@ -22,6 +22,7 @@
 #define LIBS_ACN_PDU_H_
 
 #include <stdint.h>
+#include <ola/Logging.h>
 #include <ola/acn/ACNFlags.h>
 #include <ola/io/OutputStream.h>
 #include <ola/io/OutputBuffer.h>
@@ -160,6 +161,16 @@ class PDUBlock {
  */
 template <class C>
 bool PDUBlock<C>::Pack(uint8_t *data, unsigned int *length) const {
+  if (!data) {
+    OLA_WARN << "PDUBlock::Pack: missing buffer";
+    return false;
+  }
+
+  if (!length) {
+    OLA_WARN << "PDUBock::Pack: missing length";
+    return false;
+  }
+
   bool status = true;
   unsigned int i = 0;
   typename std::vector<const C*>::const_iterator iter;
diff --git a/libs/acn/PDUTest.cpp b/libs/acn/PDUTest.cpp
index a5d86cc5d..fd6e9de05 100644
--- a/libs/acn/PDUTest.cpp
+++ b/libs/acn/PDUTest.cpp
@@ -35,11 +35,13 @@ using ola::io::OutputStream;
 
 class PDUTest: public CppUnit::TestFixture {
   CPPUNIT_TEST_SUITE(PDUTest);
+  CPPUNIT_TEST(testPDU);
   CPPUNIT_TEST(testPDUBlock);
   CPPUNIT_TEST(testBlockToOutputStream);
   CPPUNIT_TEST_SUITE_END();
 
  public:
+    void testPDU();
     void testPDUBlock();
     void testBlockToOutputStream();
 
@@ -51,6 +53,41 @@ class PDUTest: public CppUnit::TestFixture {
 CPPUNIT_TEST_SUITE_REGISTRATION(PDUTest);
 
 
+/*
+ * Test that packing a PDUBlock works.
+ */
+void PDUTest::testPDU() {
+  MockPDU pdu(0x1234, 0x2468);
+
+  OLA_ASSERT_EQ(4u, pdu.HeaderSize());
+  OLA_ASSERT_EQ(4u, pdu.DataSize());
+  OLA_ASSERT_EQ(14u, pdu.Size());
+
+  unsigned int size = pdu.Size();
+  uint8_t *data = new uint8_t[size];
+  unsigned int bytes_used = size;
+  OLA_ASSERT(pdu.Pack(data, &bytes_used));
+  OLA_ASSERT_EQ(size, bytes_used);
+
+  // test null data
+  OLA_ASSERT_FALSE(pdu.Pack(NULL, &bytes_used));
+
+  // test a null length
+  OLA_ASSERT_FALSE(pdu.Pack(data, NULL));
+
+  // test undersized buffer
+  bytes_used = size - 1;
+  OLA_ASSERT_FALSE(pdu.Pack(data, &bytes_used));
+  OLA_ASSERT_EQ(0u, bytes_used);
+
+  // test oversized buffer
+  bytes_used = size + 1;
+  OLA_ASSERT(pdu.Pack(data, &bytes_used));
+  OLA_ASSERT_EQ(size, bytes_used);
+  delete[] data;
+}
+
+
 /*
  * Test that packing a PDUBlock works.
  */
@@ -74,6 +111,24 @@ void PDUTest::testPDUBlock() {
   OLA_ASSERT_EQ(1u, *test++);
   OLA_ASSERT_EQ(2u, *test++);
   OLA_ASSERT_EQ(42u, *test);
+
+  // test null data
+  OLA_ASSERT_FALSE(block.Pack(NULL, &bytes_used));
+
+  // test a null length
+  OLA_ASSERT_FALSE(block.Pack(data, NULL));
+
+  // test undersized buffer
+  bytes_used = block_size - 1;
+  OLA_ASSERT_FALSE(block.Pack(data, &bytes_used));
+  // TODO(Peter): Work out what behaviour we want for the bytes used, it's
+  // currently the actual total used, not zero like the PDU::Pack returns
+  // OLA_ASSERT_EQ(0u, bytes_used);
+
+  // test oversized buffer
+  bytes_used = block_size + 1;
+  OLA_ASSERT(block.Pack(data, &bytes_used));
+  OLA_ASSERT_EQ(block_size, bytes_used);
   delete[] data;
 
   block.Clear();