diff --git a/src/util/test.h b/src/util/test.h
index 4f3862e..a1fcc23 100644
--- a/src/util/test.h
+++ b/src/util/test.h
@@ -29,7 +29,7 @@ void run_all_tests();
 
 #define ASSERT_EQUAL(a, b)                              \
     if (!(a == b)) {                                    \
-        printf("Assertion failed: %s == %s: ", #a, #b); \
+        printf("%s:%d: Assertion failed: %s == %s: ", __FILE__, __LINE__, #a, #b); \
         print(a);                                       \
         printf(" != ");                                 \
         print(b);                                       \
@@ -38,7 +38,7 @@ void run_all_tests();
 
 #define ASSERT_DIFFERENT(a, b) \
     if (a == b) {                                    \
-        printf("Assertion failed: %s != %s: ", #a, #b); \
+        printf("%s:%d: Assertion failed: %s != %s: ", __FILE__, __LINE__, #a, #b); \
         print(a);                                       \
         printf(" == ");                                 \
         print(b);                                       \
@@ -48,7 +48,7 @@ void run_all_tests();
 
 #define ASSERT_STR_EQUAL(a, b) \
     if (strcmp(a, b) != 0) {                                    \
-        printf("Assertion failed: %s == %s: ", #a, #b); \
+        printf("%s:%d: Assertion failed: %s == %s: ", __FILE__, __LINE__, #a, #b); \
         print(a);                                       \
         printf(" != ");                                 \
         print(b);                                       \
@@ -57,7 +57,7 @@ void run_all_tests();
 
 #define ASSERT_STR_DIFFERENT(a, b) \
     if (strcmp(a, b) == 0) {                                    \
-        printf("Assertion failed: %s != %s: ", #a, #b); \
+        printf("%s:%d: Assertion failed: %s != %s: ", __FILE__, __LINE__, #a, #b); \
         print(a);                                       \
         printf(" == ");                                 \
         print(b);                                       \
diff --git a/src/util/timer.c b/src/util/timer.c
index 7bfc71e..efe4c60 100644
--- a/src/util/timer.c
+++ b/src/util/timer.c
@@ -19,6 +19,7 @@
 #include <sys/time.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 
 #include "timer.h"
 #include "test.h"
@@ -533,6 +534,31 @@ void trigger_callback(void *arg)
     *triggered += 1;
 }
 
+typedef struct {
+    timeout *timeout;
+    int triggered;
+    bool stop;
+    bool change;
+    int change_value_ms;
+    int change_interval_ms;
+    bool add;
+    int add_value_ms;
+    int add_interval_ms;
+} TimeoutContainer;
+
+void container_callback(void *arg) {
+    TimeoutContainer *container = (TimeoutContainer *)arg;
+    container->triggered += 1;
+    if (container->stop)
+        stop_timeout(container->timeout);
+    else if (container->change)
+        change_timeout(&container->timeout, container->change_value_ms, container->change_interval_ms, container_callback, arg);
+    if (container->add) {
+        add_timeout(container->add_value_ms, container->add_interval_ms, container_callback, arg, NULL);
+        container->add = false;
+    }
+}
+
 TEST(add_timeout_simple) {
     u_int64_t origin = 2134523;
     int triggered = 0;
@@ -633,6 +659,40 @@ TEST(add_timeout_simple_two_reversed) {
     ASSERT_EQUAL(triggered, 2);
 }
 
+TEST(add_timeout_simple_inside_callback) {
+    u_int64_t origin = 2134523;
+    TimeoutContainer container;
+    bzero(&container, sizeof(container));
+
+    set_mock_time_ms(origin + 0);
+
+    container.add = true;
+    container.add_value_ms = 100;
+    container.timeout = add_timeout(200, 0, container_callback, &container, NULL);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 100);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 200);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 250);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 300);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 2);
+
+    set_mock_time_ms(origin + 500);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 2);
+}
+
 TEST(stop_timeout_simple_two) {
     u_int64_t origin = 2134523;
     int triggered = 0;
@@ -707,6 +767,39 @@ TEST(stop_timeout_simple_two_reversed) {
     ASSERT_EQUAL(triggered, 1);
 }
 
+TEST(stop_timeout_simple_inside_callback) {
+    u_int64_t origin = 2134523;
+    TimeoutContainer container;
+    bzero(&container, sizeof(container));
+
+    set_mock_time_ms(origin + 0);
+
+    container.stop = true;
+    container.timeout = add_timeout(200, 0, container_callback, &container, NULL);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 100);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 200);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 250);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 300);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 500);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+}
+
 TEST(change_timeout_simple) {
     u_int64_t origin = 2134523;
     int triggered = 0;
@@ -772,6 +865,86 @@ TEST(change_timeout_simple_two) {
     ASSERT_EQUAL(triggered, 2);
 }
 
+TEST(change_timeout_simple_inside_callback) {
+    u_int64_t origin = 2134523;
+    TimeoutContainer container;
+    bzero(&container, sizeof(container));
+
+    set_mock_time_ms(origin + 0);
+
+    container.change = true;
+    container.change_value_ms = 100;
+    container.timeout = add_timeout(200, 0, container_callback, &container, NULL);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 100);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 200);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 250);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 300);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 2);
+
+    set_mock_time_ms(origin + 350);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 2);
+
+    set_mock_time_ms(origin + 400);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 3);
+}
+
+TEST(add_change_two_timeout_simple_inside_callback) {
+    u_int64_t origin = 2134523;
+    TimeoutContainer container;
+    bzero(&container, sizeof(container));
+
+    set_mock_time_ms(origin + 0);
+
+    container.add = true;
+    container.add_value_ms = 100;
+    container.change = true;
+    container.change_value_ms = 100;
+    container.timeout = add_timeout(200, 0, container_callback, &container, NULL);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 100);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 0);
+
+    set_mock_time_ms(origin + 200);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    // Now we have two running timers, one changing itself to expire after 100 ms when triggered,
+    // the other firing once after 100 ms
+    set_mock_time_ms(origin + 250);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 1);
+
+    set_mock_time_ms(origin + 300);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 3);
+
+    set_mock_time_ms(origin + 350);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 3);
+
+    set_mock_time_ms(origin + 400);
+    handle_expired_timers();
+    ASSERT_EQUAL(container.triggered, 4);
+}
+
 int64_t timeval_to_ms(struct timeval *v)
 {
     if (!v)