diff --git a/tests/acpi-test.c b/tests/acpi-test.c
index 31f5359..cbcc849 100644
--- a/tests/acpi-test.c
+++ b/tests/acpi-test.c
@@ -551,6 +551,7 @@ static void test_acpi_asl(test_data *data)
 
 static void test_acpi_one(const char *params, test_data *data)
 {
+    QTestState *s;
     char *args;
     uint8_t signature_low;
     uint8_t signature_high;
@@ -564,7 +565,8 @@ static void test_acpi_one(const char *params, test_data *data)
 
     args = g_strdup_printf("-net none -display none %s -drive file=%s%s,",
                            params ? params : "", disk, device);
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
 
    /* Wait at most 1 minute */
 #define TEST_DELAY (1 * G_USEC_PER_SEC / 10)
diff --git a/tests/blockdev-test.c b/tests/blockdev-test.c
index c940e00..d0a8bbf 100644
--- a/tests/blockdev-test.c
+++ b/tests/blockdev-test.c
@@ -16,11 +16,13 @@
 
 static void test_drive_add_empty(void)
 {
+    QTestState *s;
     QDict *response;
     const char *response_return;
 
     /* Start with an empty drive */
-    qtest_start("-drive if=none,id=drive0");
+    s = qtest_start("-drive if=none,id=drive0");
+    g_assert(qtest_state_valid(s));
 
     /* Delete the drive */
     response = qmp("{\"execute\": \"human-monitor-command\","
diff --git a/tests/boot-order-test.c b/tests/boot-order-test.c
index 360a691..10f995d 100644
--- a/tests/boot-order-test.c
+++ b/tests/boot-order-test.c
@@ -31,6 +31,7 @@ static void test_a_boot_order(const char *machine,
                               uint64_t expected_boot,
                               uint64_t expected_reboot)
 {
+    QTestState *s;
     char *args;
     uint64_t actual;
 
@@ -38,7 +39,8 @@ static void test_a_boot_order(const char *machine,
                            machine ? " -M " : "",
                            machine ?: "",
                            test_args);
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
     actual = read_boot_order();
     g_assert_cmphex(actual, ==, expected_boot);
     qmp_discard_response("{ 'execute': 'system_reset' }");
diff --git a/tests/e1000-test.c b/tests/e1000-test.c
index a8ba2fc..2dfc18f 100644
--- a/tests/e1000-test.c
+++ b/tests/e1000-test.c
@@ -19,12 +19,15 @@ static void nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/e1000/nop", nop);
 
-    qtest_start("-device e1000");
+    s = qtest_start("-device e1000");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/eepro100-test.c b/tests/eepro100-test.c
index bf82526..19623c0 100644
--- a/tests/eepro100-test.c
+++ b/tests/eepro100-test.c
@@ -20,6 +20,7 @@ static void test_device(gconstpointer data)
 
     args = g_strdup_printf("-device %s", model);
     s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
 
     /* Tests only initialization so far. TODO: Implement functional tests */
 
diff --git a/tests/endianness-test.c b/tests/endianness-test.c
index 92e17d2..6ffe6a2 100644
--- a/tests/endianness-test.c
+++ b/tests/endianness-test.c
@@ -118,6 +118,7 @@ static void isa_outl(const TestCase *test, uint16_t addr, uint32_t value)
 
 static void test_endianness(gconstpointer data)
 {
+    QTestState *s;
     const TestCase *test = data;
     char *args;
 
@@ -125,7 +126,9 @@ static void test_endianness(gconstpointer data)
                            test->machine,
                            test->superio ? " -device " : "",
                            test->superio ?: "");
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
+
     isa_outl(test, 0xe0, 0x87654321);
     g_assert_cmphex(isa_inl(test, 0xe0), ==, 0x87654321);
     g_assert_cmphex(isa_inw(test, 0xe2), ==, 0x8765);
@@ -193,6 +196,7 @@ static void test_endianness(gconstpointer data)
 
 static void test_endianness_split(gconstpointer data)
 {
+    QTestState *s;
     const TestCase *test = data;
     char *args;
 
@@ -200,7 +204,9 @@ static void test_endianness_split(gconstpointer data)
                            test->machine,
                            test->superio ? " -device " : "",
                            test->superio ?: "");
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
+
     isa_outl(test, 0xe8, 0x87654321);
     g_assert_cmphex(isa_inl(test, 0xe0), ==, 0x87654321);
     g_assert_cmphex(isa_inw(test, 0xe2), ==, 0x8765);
@@ -240,6 +246,7 @@ static void test_endianness_split(gconstpointer data)
 
 static void test_endianness_combine(gconstpointer data)
 {
+    QTestState *s;
     const TestCase *test = data;
     char *args;
 
@@ -247,7 +254,9 @@ static void test_endianness_combine(gconstpointer data)
                            test->machine,
                            test->superio ? " -device " : "",
                            test->superio ?: "");
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
+
     isa_outl(test, 0xe0, 0x87654321);
     g_assert_cmphex(isa_inl(test, 0xe8), ==, 0x87654321);
     g_assert_cmphex(isa_inw(test, 0xea), ==, 0x8765);
diff --git a/tests/fdc-test.c b/tests/fdc-test.c
index 37096dc..cadada8 100644
--- a/tests/fdc-test.c
+++ b/tests/fdc-test.c
@@ -517,6 +517,7 @@ static void fuzz_registers(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     const char *arch = qtest_get_arch();
     int fd;
     int ret;
@@ -537,7 +538,9 @@ int main(int argc, char **argv)
     /* Run the tests */
     g_test_init(&argc, &argv, NULL);
 
-    qtest_start(NULL);
+    s = qtest_start(NULL);
+    g_assert(qtest_state_valid(s));
+
     qtest_irq_intercept_in(global_qtest, "ioapic");
     qtest_add_func("/fdc/cmos", test_cmos);
     qtest_add_func("/fdc/no_media_on_start", test_no_media_on_start);
diff --git a/tests/fw_cfg-test.c b/tests/fw_cfg-test.c
index 5c8f8d6..da03789 100644
--- a/tests/fw_cfg-test.c
+++ b/tests/fw_cfg-test.c
@@ -127,6 +127,8 @@ int main(int argc, char **argv)
 
     cmdline = g_strdup_printf("-uuid 4600cb32-38ec-4b2f-8acb-81c6ea54f2d8 ");
     s = qtest_start(cmdline);
+    g_assert(qtest_state_valid(s));
+
     g_free(cmdline);
 
     ret = g_test_run();
diff --git a/tests/hd-geo-test.c b/tests/hd-geo-test.c
index c84d1e7..636e4e2 100644
--- a/tests/hd-geo-test.c
+++ b/tests/hd-geo-test.c
@@ -239,16 +239,20 @@ static int setup_ide(int argc, char *argv[], int argv_sz,
  */
 static void test_ide_none(void)
 {
+    QTestState *s;
     char *argv[256];
 
     setup_common(argv, ARRAY_SIZE(argv));
-    qtest_start(g_strjoinv(" ", argv));
+    s = qtest_start(g_strjoinv(" ", argv));
+    g_assert(qtest_state_valid(s));
+
     test_cmos();
     qtest_end();
 }
 
 static void test_ide_mbr(bool use_device, MBRcontents mbr)
 {
+    QTestState *s;
     char *argv[256];
     int argc;
     Backend i;
@@ -260,7 +264,9 @@ static void test_ide_mbr(bool use_device, MBRcontents mbr)
         dev = use_device ? (is_hd(cur_ide[i]) ? "ide-hd" : "ide-cd") : NULL;
         argc = setup_ide(argc, argv, ARRAY_SIZE(argv), i, dev, i, mbr, "");
     }
-    qtest_start(g_strjoinv(" ", argv));
+    s = qtest_start(g_strjoinv(" ", argv));
+    g_assert(qtest_state_valid(s));
+
     test_cmos();
     qtest_end();
 }
@@ -315,6 +321,7 @@ static void test_ide_device_mbr_chs(void)
 
 static void test_ide_drive_user(const char *dev, bool trans)
 {
+    QTestState *s;
     char *argv[256], *opts;
     int argc;
     int secs = img_secs[backend_small];
@@ -332,7 +339,9 @@ static void test_ide_drive_user(const char *dev, bool trans)
                      0, dev ? opts : NULL, backend_small, mbr_chs,
                      dev ? "" : opts);
     g_free(opts);
-    qtest_start(g_strjoinv(" ", argv));
+    s = qtest_start(g_strjoinv(" ", argv));
+    g_assert(qtest_state_valid(s));
+
     test_cmos();
     qtest_end();
 }
@@ -374,6 +383,7 @@ static void test_ide_device_user_chst(void)
  */
 static void test_ide_drive_cd_0(void)
 {
+    QTestState *s;
     char *argv[256];
     int argc, ide_idx;
     Backend i;
@@ -385,7 +395,9 @@ static void test_ide_drive_cd_0(void)
         argc = setup_ide(argc, argv, ARRAY_SIZE(argv),
                          ide_idx, NULL, i, mbr_blank, "");
     }
-    qtest_start(g_strjoinv(" ", argv));
+    s = qtest_start(g_strjoinv(" ", argv));
+    g_assert(qtest_state_valid(s));
+
     test_cmos();
     qtest_end();
 }
diff --git a/tests/i440fx-test.c b/tests/i440fx-test.c
index ad232b5..b6f1add 100644
--- a/tests/i440fx-test.c
+++ b/tests/i440fx-test.c
@@ -41,10 +41,13 @@ typedef struct FirmwareTestFixture {
 
 static QPCIBus *test_start_get_bus(const TestData *s)
 {
+    QTestState *state;
     char *cmdline;
 
     cmdline = g_strdup_printf("-smp %d", s->num_cpus);
-    qtest_start(cmdline);
+    state = qtest_start(cmdline);
+    g_assert(qtest_state_valid(state));
+
     g_free(cmdline);
     return qpci_init_pc();
 }
@@ -334,6 +337,7 @@ static char *create_blob_file(void)
 static void test_i440fx_firmware(FirmwareTestFixture *fixture,
                                  gconstpointer user_data)
 {
+    QTestState *s;
     char *fw_pathname, *cmdline;
     uint8_t *buf;
     size_t i, isa_bios_size;
@@ -346,7 +350,9 @@ static void test_i440fx_firmware(FirmwareTestFixture *fixture,
                               fixture->is_bios ? "-bios" : "-pflash",
                               fw_pathname);
     g_test_message("qemu cmdline: %s", cmdline);
-    qtest_start(cmdline);
+    s = qtest_start(cmdline);
+    g_assert(qtest_state_valid(s));
+
     g_free(cmdline);
 
     /* QEMU has loaded the firmware (because qtest_start() only returns after
diff --git a/tests/ide-test.c b/tests/ide-test.c
index 4a0d97f..94c4a38 100644
--- a/tests/ide-test.c
+++ b/tests/ide-test.c
@@ -109,6 +109,7 @@ static char tmp_path[] = "/tmp/qtest.XXXXXX";
 
 static void ide_test_start(const char *cmdline_fmt, ...)
 {
+    QTestState *s;
     va_list ap;
     char *cmdline;
 
@@ -116,7 +117,9 @@ static void ide_test_start(const char *cmdline_fmt, ...)
     cmdline = g_strdup_vprintf(cmdline_fmt, ap);
     va_end(ap);
 
-    qtest_start(cmdline);
+    s = qtest_start(cmdline);
+    g_assert(qtest_state_valid(s));
+
     qtest_irq_intercept_in(global_qtest, "ioapic");
     guest_malloc = pc_alloc_init();
 }
diff --git a/tests/ipoctal232-test.c b/tests/ipoctal232-test.c
index 3ac1714..6d7323c 100644
--- a/tests/ipoctal232-test.c
+++ b/tests/ipoctal232-test.c
@@ -19,12 +19,15 @@ static void nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/ipoctal232/tpci200/nop", nop);
 
-    qtest_start("-device tpci200,id=ipack0 -device ipoctal232,bus=ipack0.0");
+    s = qtest_start("-device tpci200,id=ipack0 -device ipoctal232,bus=ipack0.0");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/m48t59-test.c b/tests/m48t59-test.c
index 71b4f28..bda53e8 100644
--- a/tests/m48t59-test.c
+++ b/tests/m48t59-test.c
@@ -251,6 +251,7 @@ int main(int argc, char **argv)
     g_test_init(&argc, &argv, NULL);
 
     s = qtest_start("-rtc clock=vm");
+    g_assert(qtest_state_valid(s));
 
     qtest_add_func("/rtc/bcd/check-time", bcd_check_time);
     qtest_add_func("/rtc/fuzz-registers", fuzz_registers);
diff --git a/tests/ne2000-test.c b/tests/ne2000-test.c
index 61a678a..85671d9 100644
--- a/tests/ne2000-test.c
+++ b/tests/ne2000-test.c
@@ -19,12 +19,15 @@ static void pci_nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/ne2000/pci/nop", pci_nop);
 
-    qtest_start("-device ne2k_pci");
+    s = qtest_start("-device ne2k_pci");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/pcnet-test.c b/tests/pcnet-test.c
index 84af4f3..0c9db5b 100644
--- a/tests/pcnet-test.c
+++ b/tests/pcnet-test.c
@@ -19,12 +19,15 @@ static void pci_nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/pcnet/pci/nop", pci_nop);
 
-    qtest_start("-device pcnet");
+    s = qtest_start("-device pcnet");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/qdev-monitor-test.c b/tests/qdev-monitor-test.c
index ba7f9cc..5f1ba62 100644
--- a/tests/qdev-monitor-test.c
+++ b/tests/qdev-monitor-test.c
@@ -17,10 +17,12 @@
 
 static void test_device_add(void)
 {
+    QTestState *s;
     QDict *response;
     QDict *error;
 
-    qtest_start("-drive if=none,id=drive0");
+    s = qtest_start("-drive if=none,id=drive0");
+    g_assert(qtest_state_valid(s));
 
     /* Make device_add fail.  If this leaks the virtio-blk-pci device then a
      * reference to drive0 will also be held (via qdev properties).
diff --git a/tests/qom-test.c b/tests/qom-test.c
index b6671fb..3b1a30e 100644
--- a/tests/qom-test.c
+++ b/tests/qom-test.c
@@ -45,12 +45,15 @@ static bool is_blacklisted(const char *arch, const char *mach)
 
 static void test_machine(gconstpointer data)
 {
+    QTestState *s;
     const char *machine = data;
     char *args;
     QDict *response;
 
     args = g_strdup_printf("-machine %s", machine);
-    qtest_start(args);
+    s = qtest_start(args);
+    g_assert(qtest_state_valid(s));
+
     response = qmp("{ 'execute': 'quit' }");
     g_assert(qdict_haskey(response, "return"));
     qtest_end();
@@ -59,6 +62,7 @@ static void test_machine(gconstpointer data)
 
 static void add_machine_test_cases(void)
 {
+    QTestState *s;
     const char *arch = qtest_get_arch();
     QDict *response, *minfo;
     QList *list;
@@ -67,7 +71,9 @@ static void add_machine_test_cases(void)
     QString *qstr;
     const char *mname, *path;
 
-    qtest_start("-machine none");
+    s = qtest_start("-machine none");
+    g_assert(qtest_state_valid(s));
+
     response = qmp("{ 'execute': 'query-machines' }");
     g_assert(response);
     list = qdict_get_qlist(response, "return");
diff --git a/tests/rtc-test.c b/tests/rtc-test.c
index 4243624..9668c4a 100644
--- a/tests/rtc-test.c
+++ b/tests/rtc-test.c
@@ -548,12 +548,14 @@ static void register_b_set_flag(void)
 
 int main(int argc, char **argv)
 {
-    QTestState *s = NULL;
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
 
     s = qtest_start("-rtc clock=vm");
+    g_assert(qtest_state_valid(s));
+
     qtest_irq_intercept_in(s, "ioapic");
 
     qtest_add_func("/rtc/check-time/bcd", bcd_check_time);
diff --git a/tests/rtl8139-test.c b/tests/rtl8139-test.c
index f6a1be3..cfb9feb 100644
--- a/tests/rtl8139-test.c
+++ b/tests/rtl8139-test.c
@@ -19,12 +19,15 @@ static void nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/rtl8139/nop", nop);
 
-    qtest_start("-device rtl8139");
+    s = qtest_start("-device rtl8139");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/tmp105-test.c b/tests/tmp105-test.c
index 0834219..565a225 100644
--- a/tests/tmp105-test.c
+++ b/tests/tmp105-test.c
@@ -55,12 +55,14 @@ static void send_and_receive(void)
 
 int main(int argc, char **argv)
 {
-    QTestState *s = NULL;
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
 
     s = qtest_start("-machine n800");
+    g_assert(qtest_state_valid(s));
+
     i2c = omap_i2c_create(OMAP2_I2C_1_BASE);
     addr = N8X0_ADDR;
 
diff --git a/tests/tpci200-test.c b/tests/tpci200-test.c
index 9ae0127..dd4e248 100644
--- a/tests/tpci200-test.c
+++ b/tests/tpci200-test.c
@@ -19,12 +19,15 @@ static void nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/tpci200/nop", nop);
 
-    qtest_start("-device tpci200");
+    s = qtest_start("-device tpci200");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/virtio-net-test.c b/tests/virtio-net-test.c
index df99343..e0b0bc5 100644
--- a/tests/virtio-net-test.c
+++ b/tests/virtio-net-test.c
@@ -19,12 +19,15 @@ static void pci_nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/virtio/net/pci/nop", pci_nop);
 
-    qtest_start("-device virtio-net-pci");
+    s = qtest_start("-device virtio-net-pci");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
diff --git a/tests/vmxnet3-test.c b/tests/vmxnet3-test.c
index a2ebed3..9546f24 100644
--- a/tests/vmxnet3-test.c
+++ b/tests/vmxnet3-test.c
@@ -19,12 +19,15 @@ static void nop(void)
 
 int main(int argc, char **argv)
 {
+    QTestState *s;
     int ret;
 
     g_test_init(&argc, &argv, NULL);
     qtest_add_func("/vmxnet3/nop", nop);
 
-    qtest_start("-device vmxnet3");
+    s = qtest_start("-device vmxnet3");
+    g_assert(qtest_state_valid(s));
+
     ret = g_test_run();
 
     qtest_end();
