diff --git a/libs/temporal/test/BBTTest.cc b/libs/temporal/test/BBTTest.cc
index 03f2a68f14..9e066e5002 100644
--- a/libs/temporal/test/BBTTest.cc
+++ b/libs/temporal/test/BBTTest.cc
@@ -1,6 +1,7 @@
 #include <stdlib.h>
 
 #include "temporal/bbt_time.h"
+#include "temporal/tempo.h"
 
 #include "BBTTest.h"
 
@@ -11,16 +12,97 @@ using namespace Temporal;
 void
 BBTTest::createTest()
 {
+	CPPUNIT_ASSERT_THROW_MESSAGE ("- zero-bar BBT_Time;", BBT_Time (0, 1, 0), IllegalBBTTimeException);
+	CPPUNIT_ASSERT_THROW_MESSAGE ("- zero-beat BBT_Time;", BBT_Time (1, 0, 0), IllegalBBTTimeException);
+	CPPUNIT_ASSERT_THROW_MESSAGE ("- zero-bar-and-beat BBT_Time;", BBT_Time (0, 0, 0), IllegalBBTTimeException);
+
+	/* This test checks that BBT_Time cannot convert ticks to beats etc., so the explicit 1920 ticks remains
+	   that in the constructed BBT_Time, rather than being converted to an additional beat. This has to be true
+	   because BBT_Time has no clue what the meter is.
+	*/
+	BBT_Time a (1, 1, 1920);
+	CPPUNIT_ASSERT(BBT_Time (1,2,0) != a);
+
+	/* by contrast, a zero-distance "walk" from that location should return a canonicalized BBT_Time, which given a 4/4 meter
+	   will be 1|2|0
+	*/
+
+	TempoMap::SharedPtr tmap (TempoMap::fetch());
+	BBT_Offset b (0, 0, 0);
+	BBT_Time r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,2,0), r);
+
 }
 
 void
 BBTTest::addTest()
 {
+	TempoMap::SharedPtr tmap (TempoMap::fetch());
+	BBT_Time a(1,1,0);
+	BBT_Offset b(1,0,0);
+	BBT_Time r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (2,1,0), r);
+
+	b = BBT_Offset (0, 1, 0);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,2,0), r);
+
+	b = BBT_Offset (0, 0, 1);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,1,1), r);
+
+	b = BBT_Offset (0, 0, ticks_per_beat - 1);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,1,ticks_per_beat - 1), r);
+
+	b = BBT_Offset (0, 0, ticks_per_beat);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,2,0), r);
+
+	b = BBT_Offset (0, 0, ticks_per_beat * 2);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,3,0), r);
+
+	/* assumes 4/4 time */
+
+	b = BBT_Offset (0, 4, 0);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (2,1,0), r);
+
+	b = BBT_Offset (1, 0, 0);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (2,1,0), r);
+
+	b = BBT_Offset (0, 0, ticks_per_beat * 4);
+	r = tmap->bbt_walk (a, b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (2,1,0), r);
+
 }
 
 void
 BBTTest::subtractTest()
 {
+	TempoMap::SharedPtr tmap (TempoMap::fetch());
+	BBT_Time a (1,1,0);
+	BBT_Offset b (1,0,0);
+	BBT_Time r = tmap->bbt_walk (a, -b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (-1,1,0), r);
+
+	b = BBT_Offset (0, 1, 0);
+	r = tmap->bbt_walk (a, -b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,-1,0), r); /* Not sure this is actually the correct answer */
+
+	b = BBT_Offset (0, 0, 1);
+	r = tmap->bbt_walk (a, -b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,1,-1), r); /* Not sure this is actually the correct answer */
+
+	b = BBT_Offset (0, 0, ticks_per_beat);
+	r = tmap->bbt_walk (a, -b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,1,-ticks_per_beat), r); /* Not sure this is actually the correct answer */
+
+	b = BBT_Offset (0, 0, ticks_per_beat + 1);
+	r = tmap->bbt_walk (a, -b);
+	CPPUNIT_ASSERT_EQUAL(BBT_Time (1,1,-(ticks_per_beat+1)), r); /* Not sure this is actually the correct answer */
 }
 
 void
@@ -37,4 +119,3 @@ void
 BBTTest::convertTest()
 {
 }
-