diff --git a/tests/daemon_test.py b/tests/daemon_test.py
index 83cd81d..6ff8c8a 100644
--- a/tests/daemon_test.py
+++ b/tests/daemon_test.py
@@ -995,7 +995,8 @@ def a_worker_line_too_long_to_relay_is_dropped_whole():
             check(d.wait_event("remote_pages_changed ", since=mark) == "remote_pages_changed 3",
                   "the line after the %d-byte one, unchanged" % size)
             with d.lock:
-                pieces = ["%d bytes" % len(e) for e in d.events[mark:] if e.startswith("x")]
+                # an empty line is a piece too: the end of a 2 MiB line whose start filled the relay buffer
+                pieces = ["%d bytes" % len(e) for e in d.events[mark:] if e.startswith("x") or not e]
             check(not pieces, "no piece of a %d-byte line reaches the controller: %s" % (size, pieces))
         # the longest line relayed arrives whole
         mark = d.mark()
diff --git a/tests/lv2_fixture.c b/tests/lv2_fixture.c
index 934fdf1..e275fb6 100644
--- a/tests/lv2_fixture.c
+++ b/tests/lv2_fixture.c
@@ -107,11 +107,13 @@ static void run(LV2_Handle instance, uint32_t frames)
 
 /* stress: the gain, with the fault STRESS_FAULT names on its first run() in the process, as tests/stress_plugin.c does
  * for CLAP: crash aborts, hang spins forever, fork leaves a process of its own session behind (its pid written to the
- * file STRESS_FORK_PIDFILE names) */
+ * file STRESS_FORK_PIDFILE names before run() returns) */
 static void fault_once(void)
 {
     static int done;
     const char *fault = getenv("STRESS_FAULT");
+    int ready[2];
+    char c;
 
     if (done || !fault)
         return;
@@ -121,23 +123,31 @@ static void fault_once(void)
     if (!strcmp(fault, "hang"))
         for (;;)
             ;
-    if (!strcmp(fault, "fork") && fork() == 0)
+    if (!strcmp(fault, "fork") && pipe(ready) == 0)
     {
-        const char *pidfile = getenv("STRESS_FORK_PIDFILE");
-
-        setsid();
-        if (pidfile)
+        if (fork() == 0)
         {
-            FILE *f = fopen(pidfile, "w");
+            const char *pidfile = getenv("STRESS_FORK_PIDFILE");
 
-            if (f)
+            setsid();
+            if (pidfile)
             {
-                fprintf(f, "%d\n", (int)getpid());
-                fclose(f);
+                FILE *f = fopen(pidfile, "w");
+
+                if (f)
+                {
+                    fprintf(f, "%d\n", (int)getpid());
+                    fclose(f);
+                }
             }
+            close(ready[1]);
+            sleep(60);
+            _exit(0);
         }
-        sleep(60);
-        _exit(0);
+        close(ready[1]);
+        while (read(ready[0], &c, 1) > 0)
+            ;
+        close(ready[0]);
     }
 }
 
diff --git a/tests/stress_plugin.c b/tests/stress_plugin.c
index f58c225..0dce30a 100644
--- a/tests/stress_plugin.c
+++ b/tests/stress_plugin.c
@@ -23,7 +23,7 @@
  *   STRESS_FAULT=crash          the first process call aborts
  *   STRESS_FAULT=hang           the first process call never returns
  *   STRESS_FAULT=fork           the first process call leaves a process behind that starts its own session and sleeps a
- *                               minute; its pid is written to the file STRESS_FORK_PIDFILE names
+ *                               minute; the call returns once its pid is written to the file STRESS_FORK_PIDFILE names
  */
 /* A stereo passthrough .clap the daemon's tests break on purpose:
  *   org.plugin-hostd.test.stress        parameters
@@ -302,6 +302,8 @@ static void fault_once(void)
 {
     static int done;
     const char *fault = getenv("STRESS_FAULT");
+    int ready[2];
+    char c;
 
     if (done || !fault)
         return;
@@ -311,7 +313,7 @@ static void fault_once(void)
     if (!strcmp(fault, "hang"))
         for (;;)
             ;
-    if (!strcmp(fault, "fork"))
+    if (!strcmp(fault, "fork") && pipe(ready) == 0)
     {
         pid_t pid = fork();
 
@@ -330,9 +332,14 @@ static void fault_once(void)
                     fclose(f);
                 }
             }
+            close(ready[1]);
             sleep(60);
             _exit(0);
         }
+        close(ready[1]);
+        while (read(ready[0], &c, 1) > 0)
+            ;
+        close(ready[0]);
     }
 }