diff --git a/tests/components/proc/asset/meta/time-grid-basics-test.cpp b/tests/components/proc/asset/meta/time-grid-basics-test.cpp
index ea98b04bc..e90eb794a 100644
--- a/tests/components/proc/asset/meta/time-grid-basics-test.cpp
+++ b/tests/components/proc/asset/meta/time-grid-basics-test.cpp
@@ -103,7 +103,7 @@ namespace test {
           Time point (myGrid->timeOf (randomFrame));
           CHECK (point == testOrigin + randomFrame * testFps.duration());
           
-          uint fract = rand() % DIRT_GRAIN;
+          uint fract = 1 + rand() % DIRT_GRAIN;
           FSecs dirt = rational_cast<FSecs> (1 / testFps / fract);
           
           Time dirty(point + Time(dirt));