diff --git a/libs/ardour/test/BBTTest.cpp b/libs/ardour/test/BBTTest.cpp
index ec32eaa81e..5f5f18b629 100644
--- a/libs/ardour/test/BBTTest.cpp
+++ b/libs/ardour/test/BBTTest.cpp
@@ -11,6 +11,10 @@ void
 BBTTest::addTest ()
 {
 	TempoMap map(48000);
+
+	// Test basic operations with a flat tempo map
+	CPPUNIT_ASSERT(map.bbt_add(BBT_Time(0, 0, 0), BBT_Time(1, 2, 3)) == BBT_Time(1, 2, 3));
+	CPPUNIT_ASSERT(map.bbt_add(BBT_Time(1, 2, 3), BBT_Time(0, 0, 0)) == BBT_Time(1, 2, 3));
 }
 
 void