diff --git a/mock/lib-time-mocks.cpp b/mock/lib-time-mocks.cpp
index 601012a..06b2ef0 100644
--- a/mock/lib-time-mocks.cpp
+++ b/mock/lib-time-mocks.cpp
@@ -1,6 +1,6 @@
 #include <rusefi/rusefi_time_math.h>
 
-int timeNowUs = 0;
+static int timeNowUs = 0;
 
 efitimeus_t getTimeNowUs() {
 	return timeNowUs;
@@ -13,3 +13,11 @@ efitimesec_t getTimeNowS() {
 efitick_t getTimeNowNt() {
 	return getTimeNowUs() * US_TO_NT_MULTIPLIER;
 }
+
+void setTimeNowUs(int us) {
+	timeNowUs = us;
+}
+
+void advanceTimeUs(int us) {
+	timeNowUs += us;
+}
diff --git a/util/include/rusefi/rusefi_time_math.h b/util/include/rusefi/rusefi_time_math.h
index 64d5001..6fdbd34 100644
--- a/util/include/rusefi/rusefi_time_math.h
+++ b/util/include/rusefi/rusefi_time_math.h
@@ -13,3 +13,9 @@
 #define NT2USF(x) (((float)(x)) / US_TO_NT_MULTIPLIER)
 
 #define NT_PER_SECOND (US2NT(US_PER_SECOND_LL))
+
+#if EFI_UNIT_TEST
+// In unit tests, we can time travel...
+void setTimeNowUs(int us);
+void advanceTimeUs(int us);
+#endif