diff --git a/lib/isc/tests/Makefile.in b/lib/isc/tests/Makefile.in
index 046b8dcff3..d743821a9e 100644
--- a/lib/isc/tests/Makefile.in
+++ b/lib/isc/tests/Makefile.in
@@ -89,9 +89,9 @@ hash_test@EXEEXT@: hash_test.@O@ ${ISCDEPLIBS}
 		${LDFLAGS} -o $@ hash_test.@O@ \
 		${ISCLIBS} ${LIBS}
 
-heap_test@EXEEXT@: heap_test.@O@ ${ISCDEPLIBS}
+heap_test@EXEEXT@: heap_test.@O@ isctest.@O@ ${ISCDEPLIBS}
 	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} \
-		${LDFLAGS} -o $@ heap_test.@O@ \
+		${LDFLAGS} -o $@ heap_test.@O@ isctest.@O@ \
 		${ISCLIBS} ${LIBS}
 
 hmac_test@EXEEXT@: hmac_test.@O@ ${ISCDEPLIBS}
@@ -99,14 +99,14 @@ hmac_test@EXEEXT@: hmac_test.@O@ ${ISCDEPLIBS}
 		${LDFLAGS} -o $@ hmac_test.@O@ \
 		${ISCLIBS} ${LIBS}
 
-ht_test@EXEEXT@: ht_test.@O@ ${ISCDEPLIBS}
+ht_test@EXEEXT@: ht_test.@O@ isctest.@O@ ${ISCDEPLIBS}
 	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} \
-		${LDFLAGS} -o $@ ht_test.@O@ \
+		${LDFLAGS} -o $@ ht_test.@O@ isctest.@O@ \
 		${ISCLIBS} ${LIBS}
 
-lex_test@EXEEXT@: lex_test.@O@ ${ISCDEPLIBS}
+lex_test@EXEEXT@: lex_test.@O@ isctest.@O@ ${ISCDEPLIBS}
 	${LIBTOOL_MODE_LINK} ${PURIFY} ${CC} ${CFLAGS} \
-		${LDFLAGS} -o $@ lex_test.@O@ \
+		${LDFLAGS} -o $@ lex_test.@O@ isctest.@O@ \
 		${ISCLIBS} ${LIBS}
 
 md_test@EXEEXT@: md_test.@O@ ${ISCDEPLIBS}
diff --git a/lib/isc/tests/buffer_test.c b/lib/isc/tests/buffer_test.c
index 80d01e04e4..71b9aa2110 100644
--- a/lib/isc/tests/buffer_test.c
+++ b/lib/isc/tests/buffer_test.c
@@ -65,7 +65,7 @@ isc_buffer_reserve_test(void **state) {
 	UNUSED(state);
 
 	b = NULL;
-	result = isc_buffer_allocate(mctx, &b, 1024);
+	result = isc_buffer_allocate(test_mctx, &b, 1024);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(b->length, 1024);
 
@@ -135,7 +135,7 @@ isc_buffer_dynamic_test(void **state) {
 	UNUSED(state);
 
 	b = NULL;
-	result = isc_buffer_allocate(mctx, &b, last_length);
+	result = isc_buffer_allocate(test_mctx, &b, last_length);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_non_null(b);
 	assert_int_equal(b->length, last_length);
@@ -194,7 +194,7 @@ isc_buffer_copyregion_test(void **state) {
 
 	UNUSED(state);
 
-	result = isc_buffer_allocate(mctx, &b, sizeof(data));
+	result = isc_buffer_allocate(test_mctx, &b, sizeof(data));
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	/*
@@ -234,7 +234,7 @@ isc_buffer_printf_test(void **state) {
 	 * Prepare a buffer with auto-reallocation enabled.
 	 */
 	b = NULL;
-	result = isc_buffer_allocate(mctx, &b, 0);
+	result = isc_buffer_allocate(test_mctx, &b, 0);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	isc_buffer_setautorealloc(b, true);
 
diff --git a/lib/isc/tests/counter_test.c b/lib/isc/tests/counter_test.c
index 6770dd2453..55ef991685 100644
--- a/lib/isc/tests/counter_test.c
+++ b/lib/isc/tests/counter_test.c
@@ -58,7 +58,7 @@ isc_counter_test(void **state) {
 
 	UNUSED(state);
 
-	result = isc_counter_create(mctx, 0, &counter);
+	result = isc_counter_create(test_mctx, 0, &counter);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	for (i = 0; i < 10; i++) {
diff --git a/lib/isc/tests/heap_test.c b/lib/isc/tests/heap_test.c
index b0b8e64481..4a6d55c665 100644
--- a/lib/isc/tests/heap_test.c
+++ b/lib/isc/tests/heap_test.c
@@ -28,6 +28,29 @@
 #include <isc/mem.h>
 #include <isc/util.h>
 
+#include "isctest.h"
+
+static int
+_setup(void **state) {
+	isc_result_t result;
+
+	UNUSED(state);
+
+	result = isc_test_begin(NULL, true, 0);
+	assert_int_equal(result, ISC_R_SUCCESS);
+
+	return (0);
+}
+
+static int
+_teardown(void **state) {
+	UNUSED(state);
+
+	isc_test_end();
+
+	return (0);
+}
+
 struct e {
 	unsigned int value;
 	unsigned int index;
@@ -51,16 +74,13 @@ idx(void *p, unsigned int i) {
 /* test isc_heap_delete() */
 static void
 isc_heap_delete_test(void **state) {
-	isc_mem_t *mctx = NULL;
 	isc_heap_t *heap = NULL;
 	isc_result_t result;
 	struct e e1 = { 100, 0 };
 
 	UNUSED(state);
 
-	isc_mem_create(&mctx);
-
-	result = isc_heap_create(mctx, compare, idx, 0, &heap);
+	result = isc_heap_create(test_mctx, compare, idx, 0, &heap);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_non_null(heap);
 
@@ -73,9 +93,6 @@ isc_heap_delete_test(void **state) {
 
 	isc_heap_destroy(&heap);
 	assert_int_equal(heap, NULL);
-
-	isc_mem_detach(&mctx);
-	assert_int_equal(mctx, NULL);
 }
 
 int
@@ -84,7 +101,7 @@ main(void) {
 		cmocka_unit_test(isc_heap_delete_test),
 	};
 
-	return (cmocka_run_group_tests(tests, NULL, NULL));
+	return (cmocka_run_group_tests(tests, _setup, _teardown));
 }
 
 #else /* HAVE_CMOCKA */
diff --git a/lib/isc/tests/ht_test.c b/lib/isc/tests/ht_test.c
index 40bfccbc75..c186614549 100644
--- a/lib/isc/tests/ht_test.c
+++ b/lib/isc/tests/ht_test.c
@@ -31,16 +31,37 @@
 #include <isc/string.h>
 #include <isc/util.h>
 
+#include "isctest.h"
+
+static int
+_setup(void **state) {
+	isc_result_t result;
+
+	UNUSED(state);
+
+	result = isc_test_begin(NULL, true, 0);
+	assert_int_equal(result, ISC_R_SUCCESS);
+
+	return (0);
+}
+
+static int
+_teardown(void **state) {
+	UNUSED(state);
+
+	isc_test_end();
+
+	return (0);
+}
+
+
 static void
 test_ht_full(int bits, uintptr_t count) {
 	isc_ht_t *ht = NULL;
 	isc_result_t result;
-	isc_mem_t *mctx = NULL;
 	uintptr_t i;
 
-	isc_mem_create(&mctx);
-
-	result = isc_ht_init(&ht, mctx, bits);
+	result = isc_ht_init(&ht, test_mctx, bits);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_non_null(ht);
 
@@ -174,15 +195,12 @@ test_ht_full(int bits, uintptr_t count) {
 
 	isc_ht_destroy(&ht);
 	assert_null(ht);
-
-	isc_mem_detach(&mctx);
 }
 
 static void
 test_ht_iterator() {
 	isc_ht_t *ht = NULL;
 	isc_result_t result;
-	isc_mem_t *mctx = NULL;
 	isc_ht_iter_t * iter = NULL;
 	uintptr_t i;
 	uintptr_t count = 10000;
@@ -190,9 +208,7 @@ test_ht_iterator() {
 	unsigned char key[16];
 	size_t tksize;
 
-	isc_mem_create(&mctx);
-
-	result = isc_ht_init(&ht, mctx, 16);
+	result = isc_ht_init(&ht, test_mctx, 16);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_non_null(ht);
 	for (i = 1; i <= count; i++) {
@@ -293,8 +309,6 @@ test_ht_iterator() {
 
 	isc_ht_destroy(&ht);
 	assert_null(ht);
-
-	isc_mem_detach(&mctx);
 }
 
 /* 20 bit, 200K elements test */
@@ -335,7 +349,7 @@ main(void) {
 		cmocka_unit_test(isc_ht_iterator_test),
 	};
 
-	return (cmocka_run_group_tests(tests, NULL, NULL));
+	return (cmocka_run_group_tests(tests, _setup, _teardown));
 }
 
 #else /* HAVE_CMOCKA */
diff --git a/lib/isc/tests/isctest.c b/lib/isc/tests/isctest.c
index 08ced36b30..e3d59611e7 100644
--- a/lib/isc/tests/isctest.c
+++ b/lib/isc/tests/isctest.c
@@ -28,8 +28,8 @@
 
 #include "isctest.h"
 
-isc_mem_t *mctx = NULL;
-isc_log_t *lctx = NULL;
+isc_mem_t *test_mctx = NULL;
+isc_log_t *test_lctx = NULL;
 isc_taskmgr_t *taskmgr = NULL;
 isc_timermgr_t *timermgr = NULL;
 isc_socketmgr_t *socketmgr = NULL;
@@ -56,9 +56,6 @@ static isc_logcategory_t categories[] = {
 
 static void
 cleanup_managers(void) {
-	if (netmgr != NULL) {
-		isc_nm_detach(&netmgr);
-	}
 	if (maintask != NULL) {
 		isc_task_shutdown(maintask);
 		isc_task_destroy(&maintask);
@@ -72,6 +69,9 @@ cleanup_managers(void) {
 	if (timermgr != NULL) {
 		isc_timermgr_destroy(&timermgr);
 	}
+	if (netmgr != NULL) {
+		isc_nm_detach(&netmgr);
+	}
 }
 
 static isc_result_t
@@ -88,13 +88,13 @@ create_managers(unsigned int workers) {
 		workers = atoi(p);
 	}
 
-	CHECK(isc_taskmgr_create(mctx, workers, 0, NULL, &taskmgr));
+	netmgr = isc_nm_start(test_mctx, workers);
+	CHECK(isc_taskmgr_create(test_mctx, workers, 0, netmgr, &taskmgr));
 	CHECK(isc_task_create(taskmgr, 0, &maintask));
 	isc_taskmgr_setexcltask(taskmgr, maintask);
 
-	CHECK(isc_timermgr_create(mctx, &timermgr));
-	CHECK(isc_socketmgr_create(mctx, &socketmgr));
-	netmgr = isc_nm_start(mctx, 3);
+	CHECK(isc_timermgr_create(test_mctx, &timermgr));
+	CHECK(isc_socketmgr_create(test_mctx, &socketmgr));
 	return (ISC_R_SUCCESS);
 
  cleanup:
@@ -113,18 +113,18 @@ isc_test_begin(FILE *logfile, bool start_managers,
 
 	isc_mem_debugging |= ISC_MEM_DEBUGRECORD;
 
-	INSIST(mctx == NULL);
-	isc_mem_create(&mctx);
+	INSIST(test_mctx == NULL);
+	isc_mem_create(&test_mctx);
 
 	if (logfile != NULL) {
 		isc_logdestination_t destination;
 		isc_logconfig_t *logconfig = NULL;
 
-		INSIST(lctx == NULL);
-		CHECK(isc_log_create(mctx, &lctx, &logconfig));
+		INSIST(test_lctx == NULL);
+		CHECK(isc_log_create(test_mctx, &test_lctx, &logconfig));
 
-		isc_log_registercategories(lctx, categories);
-		isc_log_setcontext(lctx);
+		isc_log_registercategories(test_lctx, categories);
+		isc_log_setcontext(test_lctx);
 
 		destination.file.stream = logfile;
 		destination.file.name = NULL;
@@ -161,11 +161,11 @@ isc_test_end(void) {
 
 	cleanup_managers();
 
-	if (lctx != NULL) {
-		isc_log_destroy(&lctx);
+	if (test_lctx != NULL) {
+		isc_log_destroy(&test_lctx);
 	}
-	if (mctx != NULL) {
-		isc_mem_destroy(&mctx);
+	if (test_mctx != NULL) {
+		isc_mem_destroy(&test_mctx);
 	}
 
 	test_running = false;
diff --git a/lib/isc/tests/isctest.h b/lib/isc/tests/isctest.h
index c89996721a..17b0342d23 100644
--- a/lib/isc/tests/isctest.h
+++ b/lib/isc/tests/isctest.h
@@ -33,8 +33,8 @@
 			goto cleanup; \
 	} while (0)
 
-extern isc_mem_t *mctx;
-extern isc_log_t *lctx;
+extern isc_mem_t *test_mctx;
+extern isc_log_t *test_lctx;
 extern isc_taskmgr_t *taskmgr;
 extern isc_timermgr_t *timermgr;
 extern isc_socketmgr_t *socketmgr;
diff --git a/lib/isc/tests/lex_test.c b/lib/isc/tests/lex_test.c
index 462375ae93..709574e0e3 100644
--- a/lib/isc/tests/lex_test.c
+++ b/lib/isc/tests/lex_test.c
@@ -28,10 +28,32 @@
 #include <isc/mem.h>
 #include <isc/util.h>
 
+#include "isctest.h"
+
+static int
+_setup(void **state) {
+	isc_result_t result;
+
+	UNUSED(state);
+
+	result = isc_test_begin(NULL, true, 0);
+	assert_int_equal(result, ISC_R_SUCCESS);
+
+	return (0);
+}
+
+static int
+_teardown(void **state) {
+	UNUSED(state);
+
+	isc_test_end();
+
+	return (0);
+}
+
 /* check handling of 0xff */
 static void
 lex_0xff(void **state) {
-	isc_mem_t *mctx = NULL;
 	isc_result_t result;
 	isc_lex_t *lex = NULL;
 	isc_buffer_t death_buf;
@@ -41,9 +63,7 @@ lex_0xff(void **state) {
 
 	UNUSED(state);
 
-	isc_mem_create(&mctx);
-
-	result = isc_lex_create(mctx, 1024, &lex);
+	result = isc_lex_create(test_mctx, 1024, &lex);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	isc_buffer_init(&death_buf, &death[0], sizeof(death));
@@ -56,14 +76,11 @@ lex_0xff(void **state) {
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	isc_lex_destroy(&lex);
-
-	isc_mem_destroy(&mctx);
 }
 
 /* check setting of source line */
 static void
 lex_setline(void **state) {
-	isc_mem_t *mctx = NULL;
 	isc_result_t result;
 	isc_lex_t *lex = NULL;
 	unsigned char text[] = "text\nto\nbe\nprocessed\nby\nlexer";
@@ -74,9 +91,7 @@ lex_setline(void **state) {
 
 	UNUSED(state);
 
-	isc_mem_create(&mctx);
-
-	result = isc_lex_create(mctx, 1024, &lex);
+	result = isc_lex_create(test_mctx, 1024, &lex);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	isc_buffer_init(&buf, &text[0], sizeof(text));
@@ -103,8 +118,6 @@ lex_setline(void **state) {
 	assert_int_equal(line, 105U);
 
 	isc_lex_destroy(&lex);
-
-	isc_mem_destroy(&mctx);
 }
 
 int
@@ -114,7 +127,7 @@ main(void) {
 		cmocka_unit_test(lex_setline),
 	};
 
-	return (cmocka_run_group_tests(tests, NULL, NULL));
+	return (cmocka_run_group_tests(tests, _setup, _teardown));
 }
 
 #else /* HAVE_CMOCKA */
diff --git a/lib/isc/tests/mem_test.c b/lib/isc/tests/mem_test.c
index 0f783422e6..c1c63be610 100644
--- a/lib/isc/tests/mem_test.c
+++ b/lib/isc/tests/mem_test.c
@@ -73,19 +73,16 @@ isc_mem_test(void **state) {
 	void *items1[50];
 	void *items2[50];
 	void *tmp;
-	isc_mem_t *localmctx = NULL;
 	isc_mempool_t *mp1 = NULL, *mp2 = NULL;
 	unsigned int i, j;
 	int rval;
 
 	UNUSED(state);
 
-	isc_mem_create(&localmctx);
-
-	result = isc_mempool_create(localmctx, 24, &mp1);
+	result = isc_mempool_create(test_mctx, 24, &mp1);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
-	result = isc_mempool_create(localmctx, 31, &mp2);
+	result = isc_mempool_create(test_mctx, 31, &mp2);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	isc_mempool_setfreemax(mp1, MP1_FREEMAX);
@@ -151,11 +148,7 @@ isc_mem_test(void **state) {
 	isc_mempool_destroy(&mp1);
 	isc_mempool_destroy(&mp2);
 
-	isc_mem_destroy(&localmctx);
-
-	isc_mem_create(&localmctx);
-
-	result = isc_mempool_create(localmctx, 2, &mp1);
+	result = isc_mempool_create(test_mctx, 2, &mp1);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	tmp = isc_mempool_get(mp1);
@@ -164,9 +157,6 @@ isc_mem_test(void **state) {
 	isc_mempool_put(mp1, tmp);
 
 	isc_mempool_destroy(&mp1);
-
-	isc_mem_destroy(&localmctx);
-
 }
 
 /* test TotalUse calculation */
@@ -200,16 +190,16 @@ isc_mem_total_test(void **state) {
 
 	/* ISC_MEMFLAG_INTERNAL */
 
-	before = isc_mem_total(mctx);
+	before = isc_mem_total(test_mctx);
 
 	for (i = 0; i < 100000; i++) {
 		void *ptr;
 
-		ptr = isc_mem_allocate(mctx, 2048);
-		isc_mem_free(mctx, ptr);
+		ptr = isc_mem_allocate(test_mctx, 2048);
+		isc_mem_free(test_mctx, ptr);
 	}
 
-	after = isc_mem_total(mctx);
+	after = isc_mem_total(test_mctx);
 	diff = after - before;
 
 	/* 2048 +8 bytes extra for size_info */
@@ -397,10 +387,10 @@ mem_thread(void *arg) {
 
 	for (int i = 0; i < ITERS; i++) {
 		for (int j = 0; j < NUM_ITEMS; j++) {
-			items[j] = isc_mem_get(mctx, size);
+			items[j] = isc_mem_get(test_mctx, size);
 		}
 		for (int j = 0; j < NUM_ITEMS; j++) {
-			isc_mem_put(mctx, items[j], size);
+			isc_mem_put(test_mctx, items[j], size);
 		}
 	}
 
@@ -470,7 +460,7 @@ isc_mempool_benchmark(void **state) {
 
 	isc_mutex_init(&mplock);
 
-	result = isc_mempool_create(mctx, ITEM_SIZE, &mp);
+	result = isc_mempool_create(test_mctx, ITEM_SIZE, &mp);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	isc_mempool_associatelock(mp, &mplock);
diff --git a/lib/isc/tests/pool_test.c b/lib/isc/tests/pool_test.c
index b902869b86..5f803632f8 100644
--- a/lib/isc/tests/pool_test.c
+++ b/lib/isc/tests/pool_test.c
@@ -79,7 +79,7 @@ create_pool(void **state) {
 
 	UNUSED(state);
 
-	result = isc_pool_create(mctx, 8, poolfree, poolinit, taskmgr, &pool);
+	result = isc_pool_create(test_mctx, 8, poolfree, poolinit, taskmgr, &pool);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_pool_count(pool), 8);
 
@@ -95,7 +95,7 @@ expand_pool(void **state) {
 
 	UNUSED(state);
 
-	result = isc_pool_create(mctx, 10, poolfree, poolinit, taskmgr, &pool1);
+	result = isc_pool_create(test_mctx, 10, poolfree, poolinit, taskmgr, &pool1);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_pool_count(pool1), 10);
 
@@ -141,7 +141,7 @@ get_objects(void **state) {
 
 	UNUSED(state);
 
-	result = isc_pool_create(mctx, 2, poolfree, poolinit, taskmgr, &pool);
+	result = isc_pool_create(test_mctx, 2, poolfree, poolinit, taskmgr, &pool);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_pool_count(pool), 2);
 
diff --git a/lib/isc/tests/radix_test.c b/lib/isc/tests/radix_test.c
index 5f49ac08fd..26fd006fff 100644
--- a/lib/isc/tests/radix_test.c
+++ b/lib/isc/tests/radix_test.c
@@ -63,7 +63,7 @@ isc_radix_search_test(void **state) {
 
 	UNUSED(state);
 
-	result = isc_radix_create(mctx, &radix, 32);
+	result = isc_radix_create(test_mctx, &radix, 32);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	in_addr.s_addr = inet_addr("3.3.3.0");
diff --git a/lib/isc/tests/random_test.c b/lib/isc/tests/random_test.c
index 556acffa4b..1dbdf0068a 100644
--- a/lib/isc/tests/random_test.c
+++ b/lib/isc/tests/random_test.c
@@ -39,6 +39,8 @@
 #include <isc/result.h>
 #include <isc/util.h>
 
+#include "isctest.h"
+
 #define REPS 25000
 
 typedef double (pvalue_func_t)(isc_mem_t *mctx,
@@ -74,6 +76,27 @@ typedef enum {
 	ISC_NONCE_BYTES
 } isc_random_func;
 
+static int
+_setup(void **state) {
+	isc_result_t result;
+
+	UNUSED(state);
+
+	result = isc_test_begin(NULL, true, 0);
+	assert_int_equal(result, ISC_R_SUCCESS);
+
+	return (0);
+}
+
+static int
+_teardown(void **state) {
+	UNUSED(state);
+
+	isc_test_end();
+
+	return (0);
+}
+
 static double
 igamc(double a, double x) {
 	double ans, ax, c, yc, r, t, y, z;
@@ -272,7 +295,6 @@ matrix_binaryrank(uint32_t *bits, size_t rows, size_t cols) {
 
 static void
 random_test(pvalue_func_t *func, isc_random_func test_func) {
-	isc_mem_t *mctx = NULL;
 	uint32_t m;
 	uint32_t j;
 	uint32_t histogram[11] = { 0 };
@@ -286,8 +308,6 @@ random_test(pvalue_func_t *func, isc_random_func test_func) {
 
 	tables_init();
 
-	isc_mem_create(&mctx);
-
 	m = 1000;
 	passed = 0;
 
@@ -334,7 +354,7 @@ random_test(pvalue_func_t *func, isc_random_func test_func) {
 			break;
 		}
 
-		p_value = (*func)(mctx, (uint16_t *)values, REPS * 2);
+		p_value = (*func)(test_mctx, (uint16_t *)values, REPS * 2);
 		if (p_value >= 0.01) {
 			passed++;
 		}
@@ -841,7 +861,7 @@ main(int argc, char **argv) {
 		}
 	}
 
-	return (cmocka_run_group_tests(tests, NULL, NULL));
+	return (cmocka_run_group_tests(tests, _setup, _teardown));
 }
 
 #else /* HAVE_CMOCKA */
diff --git a/lib/isc/tests/socket_test.c b/lib/isc/tests/socket_test.c
index 20cf26b22d..77c2475f87 100644
--- a/lib/isc/tests/socket_test.c
+++ b/lib/isc/tests/socket_test.c
@@ -358,7 +358,7 @@ udp_dscp_v4_test(void **state) {
 
 	completion_init(&completion);
 
-	socketevent = isc_socket_socketevent(mctx, s1, ISC_SOCKEVENT_SENDDONE,
+	socketevent = isc_socket_socketevent(test_mctx, s1, ISC_SOCKEVENT_SENDDONE,
 					     event_done, &completion);
 	assert_non_null(socketevent);
 
@@ -452,7 +452,7 @@ udp_dscp_v6_test(void **state) {
 
 	completion_init(&completion);
 
-	socketevent = isc_socket_socketevent(mctx, s1, ISC_SOCKEVENT_SENDDONE,
+	socketevent = isc_socket_socketevent(test_mctx, s1, ISC_SOCKEVENT_SENDDONE,
 					     event_done, &completion);
 	assert_non_null(socketevent);
 
@@ -769,7 +769,7 @@ udp_trunc_test(void **state) {
 
 	completion_init(&completion);
 
-	socketevent = isc_socket_socketevent(mctx, s1, ISC_SOCKEVENT_SENDDONE,
+	socketevent = isc_socket_socketevent(test_mctx, s1, ISC_SOCKEVENT_SENDDONE,
 					     event_done, &completion);
 	assert_non_null(socketevent);
 
@@ -801,7 +801,7 @@ udp_trunc_test(void **state) {
 
 	completion_init(&completion);
 
-	socketevent = isc_socket_socketevent(mctx, s1, ISC_SOCKEVENT_SENDDONE,
+	socketevent = isc_socket_socketevent(test_mctx, s1, ISC_SOCKEVENT_SENDDONE,
 					     event_done, &completion);
 	assert_non_null(socketevent);
 
diff --git a/lib/isc/tests/symtab_test.c b/lib/isc/tests/symtab_test.c
index fea0cda699..28bb053831 100644
--- a/lib/isc/tests/symtab_test.c
+++ b/lib/isc/tests/symtab_test.c
@@ -55,8 +55,8 @@ undefine(char *key, unsigned int type, isc_symvalue_t value, void *arg) {
 	UNUSED(arg);
 
 	assert_int_equal(type, 1);
-	isc_mem_free(mctx, key);
-	isc_mem_free(mctx, value.as_pointer);
+	isc_mem_free(test_mctx, key);
+	isc_mem_free(test_mctx, value.as_pointer);
 }
 
 /* test symbol table growth */
@@ -70,7 +70,7 @@ symtab_grow(void **state) {
 
 	UNUSED(state);
 
-	result = isc_symtab_create(mctx, 3, undefine, NULL, false, &st);
+	result = isc_symtab_create(test_mctx, 3, undefine, NULL, false, &st);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_non_null(st);
 
@@ -84,9 +84,9 @@ symtab_grow(void **state) {
 		char str[16], *key;
 
 		snprintf(str, sizeof(str), "%04x", i);
-		key = isc_mem_strdup(mctx, str);
+		key = isc_mem_strdup(test_mctx, str);
 		assert_non_null(key);
-		value.as_pointer = isc_mem_strdup(mctx, str);
+		value.as_pointer = isc_mem_strdup(test_mctx, str);
 		assert_non_null(value.as_pointer);
 		result = isc_symtab_define(st, key, 1, value, policy);
 		assert_int_equal(result, ISC_R_SUCCESS);
@@ -101,9 +101,9 @@ symtab_grow(void **state) {
 		char str[16], *key;
 
 		snprintf(str, sizeof(str), "%04x", i);
-		key = isc_mem_strdup(mctx, str);
+		key = isc_mem_strdup(test_mctx, str);
 		assert_non_null(key);
-		value.as_pointer = isc_mem_strdup(mctx, str);
+		value.as_pointer = isc_mem_strdup(test_mctx, str);
 		assert_non_null(value.as_pointer);
 		result = isc_symtab_define(st, key, 1, value, policy);
 		assert_int_equal(result, ISC_R_EXISTS);
diff --git a/lib/isc/tests/task_test.c b/lib/isc/tests/task_test.c
index 9b15897a94..d44aee5898 100644
--- a/lib/isc/tests/task_test.c
+++ b/lib/isc/tests/task_test.c
@@ -167,14 +167,14 @@ all_events(void **state) {
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	/* First event */
-	event = isc_event_allocate(mctx, task, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task, ISC_TASKEVENT_TEST,
 				   set, &a, sizeof (isc_event_t));
 	assert_non_null(event);
 
 	assert_int_equal(atomic_load(&a), 0);
 	isc_task_send(task, &event);
 
-	event = isc_event_allocate(mctx, task, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task, ISC_TASKEVENT_TEST,
 				   set, &b, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -229,7 +229,7 @@ privileged_events(void **state) {
 	assert_false(isc_task_privilege(task2));
 
 	/* First event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set, &a, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -237,7 +237,7 @@ privileged_events(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Second event: not privileged */
-	event = isc_event_allocate(mctx, task2, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task2, ISC_TASKEVENT_TEST,
 				   set, &b, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -245,7 +245,7 @@ privileged_events(void **state) {
 	isc_task_send(task2, &event);
 
 	/* Third event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set, &c, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -253,7 +253,7 @@ privileged_events(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Fourth event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set, &d, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -261,7 +261,7 @@ privileged_events(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Fifth event: not privileged */
-	event = isc_event_allocate(mctx, task2, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task2, ISC_TASKEVENT_TEST,
 				   set, &e, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -350,7 +350,7 @@ privilege_drop(void **state) {
 	assert_false(isc_task_privilege(task2));
 
 	/* First event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set_and_drop, &a, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -358,7 +358,7 @@ privilege_drop(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Second event: not privileged */
-	event = isc_event_allocate(mctx, task2, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task2, ISC_TASKEVENT_TEST,
 				   set_and_drop, &b, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -366,7 +366,7 @@ privilege_drop(void **state) {
 	isc_task_send(task2, &event);
 
 	/* Third event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set_and_drop, &c, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -374,7 +374,7 @@ privilege_drop(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Fourth event: privileged */
-	event = isc_event_allocate(mctx, task1, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task1, ISC_TASKEVENT_TEST,
 				   set_and_drop, &d, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -382,7 +382,7 @@ privilege_drop(void **state) {
 	isc_task_send(task1, &event);
 
 	/* Fifth event: not privileged */
-	event = isc_event_allocate(mctx, task2, ISC_TASKEVENT_TEST,
+	event = isc_event_allocate(test_mctx, task2, ISC_TASKEVENT_TEST,
 				   set_and_drop, &e, sizeof (isc_event_t));
 	assert_non_null(event);
 
@@ -551,7 +551,7 @@ basic(void **state) {
 		 * structure (socket, timer, task, etc) but this is just a
 		 * test program.
 		 */
-		event = isc_event_allocate(mctx, (void *)1, 1, basic_cb,
+		event = isc_event_allocate(test_mctx, (void *)1, 1, basic_cb,
 					   testarray[i], sizeof(*event));
 		assert_non_null(event);
 		isc_task_send(task1, &event);
@@ -653,12 +653,12 @@ task_exclusive(void **state) {
 			isc_taskmgr_setexcltask(taskmgr, tasks[6]);
 		}
 
-		v = isc_mem_get(mctx, sizeof *v);
+		v = isc_mem_get(test_mctx, sizeof *v);
 		assert_non_null(v);
 
 		*v = i;
 
-		event = isc_event_allocate(mctx, NULL, 1, exclusive_cb,
+		event = isc_event_allocate(test_mctx, NULL, 1, exclusive_cb,
 					   v, sizeof(*event));
 		assert_non_null(event);
 
@@ -718,6 +718,7 @@ maxtask_cb(isc_task_t *task, isc_event_t *event) {
 
 static void
 manytasks(void **state) {
+	isc_mem_t *mctx = NULL;
 	isc_result_t result;
 	isc_event_t *event = NULL;
 	uintptr_t ntasks = 10000;
@@ -851,7 +852,7 @@ shutdown(void **state) {
 	/*
 	 * This event causes the task to wait on cv.
 	 */
-	event = isc_event_allocate(mctx, &senders[1], event_type, sd_event1,
+	event = isc_event_allocate(test_mctx, &senders[1], event_type, sd_event1,
 				   NULL, sizeof(*event));
 	assert_non_null(event);
 	isc_task_send(task, &event);
@@ -860,7 +861,7 @@ shutdown(void **state) {
 	 * Now we fill up the task's event queue with some events.
 	 */
 	for (i = 0; i < 256; ++i) {
-		event = isc_event_allocate(mctx, &senders[1], event_type,
+		event = isc_event_allocate(test_mctx, &senders[1], event_type,
 					   sd_event2, NULL, sizeof(*event));
 		assert_non_null(event);
 		isc_task_send(task, &event);
@@ -942,7 +943,7 @@ post_shutdown(void **state) {
 	/*
 	 * This event causes the task to wait on cv.
 	 */
-	event = isc_event_allocate(mctx, &senders[1], event_type, psd_event1,
+	event = isc_event_allocate(test_mctx, &senders[1], event_type, psd_event1,
 				   NULL, sizeof(*event));
 	assert_non_null(event);
 	isc_task_send(task, &event);
@@ -1083,7 +1084,7 @@ test_purge(int sender, int type, int tag, int exp_purged) {
 	/*
 	 * Block the task on cv.
 	 */
-	event = isc_event_allocate(mctx, (void *)1, 9999,
+	event = isc_event_allocate(test_mctx, (void *)1, 9999,
 				   pg_event1, NULL, sizeof(*event));
 
 	assert_non_null(event);
@@ -1098,7 +1099,7 @@ test_purge(int sender, int type, int tag, int exp_purged) {
 		for (type_cnt = 0; type_cnt < TYPECNT; ++type_cnt) {
 			for (tag_cnt = 0; tag_cnt < TAGCNT; ++tag_cnt) {
 				eventtab[event_cnt] =
-					isc_event_allocate(mctx,
+					isc_event_allocate(test_mctx,
 					    &senders[sender + sender_cnt],
 					    (isc_eventtype_t)(type + type_cnt),
 					    pg_event2, NULL, sizeof(*event));
@@ -1382,12 +1383,12 @@ try_purgeevent(bool purgeable) {
 	/*
 	 * Block the task on cv.
 	 */
-	event1 = isc_event_allocate(mctx, (void *)1, (isc_eventtype_t)1,
+	event1 = isc_event_allocate(test_mctx, (void *)1, (isc_eventtype_t)1,
 				    pge_event1, NULL, sizeof(*event1));
 	assert_non_null(event1);
 	isc_task_send(task, &event1);
 
-	event2 = isc_event_allocate(mctx, (void *)1, (isc_eventtype_t)1,
+	event2 = isc_event_allocate(test_mctx, (void *)1, (isc_eventtype_t)1,
 				    pge_event2, NULL, sizeof(*event2));
 	assert_non_null(event2);
 
diff --git a/lib/isc/tests/taskpool_test.c b/lib/isc/tests/taskpool_test.c
index 0dfdc0b93e..9621690bb5 100644
--- a/lib/isc/tests/taskpool_test.c
+++ b/lib/isc/tests/taskpool_test.c
@@ -58,7 +58,7 @@ create_pool(void **state) {
 
 	UNUSED(state);
 
-	result = isc_taskpool_create(taskmgr, mctx, 8, 2, &pool);
+	result = isc_taskpool_create(taskmgr, test_mctx, 8, 2, &pool);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_taskpool_size(pool), 8);
 
@@ -74,7 +74,7 @@ expand_pool(void **state) {
 
 	UNUSED(state);
 
-	result = isc_taskpool_create(taskmgr, mctx, 10, 2, &pool1);
+	result = isc_taskpool_create(taskmgr, test_mctx, 10, 2, &pool1);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_taskpool_size(pool1), 10);
 
@@ -119,7 +119,7 @@ get_tasks(void **state) {
 
 	UNUSED(state);
 
-	result = isc_taskpool_create(taskmgr, mctx, 2, 2, &pool);
+	result = isc_taskpool_create(taskmgr, test_mctx, 2, 2, &pool);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_taskpool_size(pool), 2);
 
@@ -150,7 +150,7 @@ set_privilege(void **state) {
 
 	UNUSED(state);
 
-	result = isc_taskpool_create(taskmgr, mctx, 2, 2, &pool);
+	result = isc_taskpool_create(taskmgr, test_mctx, 2, 2, &pool);
 	assert_int_equal(result, ISC_R_SUCCESS);
 	assert_int_equal(isc_taskpool_size(pool), 2);
 
diff --git a/lib/isc/tests/timer_test.c b/lib/isc/tests/timer_test.c
index 829019986b..22325d4a38 100644
--- a/lib/isc/tests/timer_test.c
+++ b/lib/isc/tests/timer_test.c
@@ -36,6 +36,8 @@
 
 #include "isctest.h"
 
+#include "../timer.c"
+
 /* Set to true (or use -v option) for verbose output */
 static bool verbose = false;
 
@@ -46,10 +48,12 @@ static isc_timer_t *timer = NULL;
 static isc_condition_t cv;
 static isc_mutex_t mx;
 static isc_time_t endtime;
+static isc_mutex_t lasttime_mx = PTHREAD_MUTEX_INITIALIZER;
 static isc_time_t lasttime;
 static int seconds;
 static int nanoseconds;
 static atomic_int_fast32_t eventcnt;
+static atomic_uint_fast32_t errcnt;
 static int nevents;
 
 static int
@@ -62,6 +66,8 @@ _setup(void **state) {
 	result = isc_test_begin(NULL, true, 2);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
+	atomic_init(&errcnt, ISC_R_SUCCESS);
+
 	return (0);
 }
 
@@ -117,7 +123,9 @@ setup_test(isc_timertype_t timertype, isc_time_t *expires,
 	result = isc_task_onshutdown(task, shutdown, NULL);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
+	isc_mutex_lock(&lasttime_mx);
 	result = isc_time_now(&lasttime);
+	isc_mutex_unlock(&lasttime_mx);
 	assert_int_equal(result, ISC_R_SUCCESS);
 
 	result = isc_timer_create(timermgr, timertype, expires, interval,
@@ -135,11 +143,41 @@ setup_test(isc_timertype_t timertype, isc_time_t *expires,
 
 	UNLOCK(&mx);
 
+	assert_int_equal(atomic_load(&errcnt), ISC_R_SUCCESS);
+
 	isc_task_detach(&task);
 	isc_mutex_destroy(&mx);
 	(void) isc_condition_destroy(&cv);
 }
 
+static void
+set_global_error(isc_result_t result) {
+	(void)atomic_compare_exchange_strong(&errcnt,
+					     &(uint_fast32_t){ ISC_R_SUCCESS },
+					     result);
+}
+
+static void
+subthread_assert_true(bool expected) {
+	if (!expected) {
+		set_global_error(ISC_R_UNEXPECTED);
+	}
+}
+
+static void
+subthread_assert_int_equal(int observed, int expected) {
+	if (observed != expected) {
+		set_global_error(ISC_R_UNEXPECTED);
+	}
+}
+
+static void
+subthread_assert_result_equal(isc_result_t result, isc_result_t expected) {
+	if (result != expected) {
+		set_global_error(result);
+	}
+}
+
 static void
 ticktock(isc_task_t *task, isc_event_t *event) {
 	isc_result_t result;
@@ -167,26 +205,33 @@ ticktock(isc_task_t *task, isc_event_t *event) {
 	}
 
 	result = isc_time_now(&now);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, seconds, nanoseconds);
+	isc_mutex_lock(&lasttime_mx);
 	result = isc_time_add(&lasttime, &interval, &base);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	isc_mutex_unlock(&lasttime_mx);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, FUDGE_SECONDS, FUDGE_NANOSECONDS);
 	result = isc_time_add(&base, &interval, &ulim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	result = isc_time_subtract(&base, &interval, &llim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
-	assert_true(isc_time_compare(&llim, &now) <= 0);
-	assert_true(isc_time_compare(&ulim, &now) >= 0);
-	lasttime = now;
+	subthread_assert_true(isc_time_compare(&llim, &now) <= 0);
+	subthread_assert_true(isc_time_compare(&ulim, &now) >= 0);
+
+	isc_interval_set(&interval, 0, 0);
+	isc_mutex_lock(&lasttime_mx);
+	result = isc_time_add(&now, &interval, &lasttime);
+	isc_mutex_unlock(&lasttime_mx);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	if (atomic_load(&eventcnt) == nevents) {
 		result = isc_time_now(&endtime);
-		assert_int_equal(result, ISC_R_SUCCESS);
+		subthread_assert_result_equal(result, ISC_R_SUCCESS);
 		isc_timer_detach(&timer);
 		isc_task_shutdown(task);
 	}
@@ -254,24 +299,30 @@ test_idle(isc_task_t *task, isc_event_t *event) {
 	}
 
 	result = isc_time_now(&now);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, seconds, nanoseconds);
+	isc_mutex_lock(&lasttime_mx);
 	result = isc_time_add(&lasttime, &interval, &base);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	isc_mutex_unlock(&lasttime_mx);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, FUDGE_SECONDS, FUDGE_NANOSECONDS);
 	result = isc_time_add(&base, &interval, &ulim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	result = isc_time_subtract(&base, &interval, &llim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
-	assert_true(isc_time_compare(&llim, &now) <= 0);
-	assert_true(isc_time_compare(&ulim, &now) >= 0);
-	lasttime = now;
+	subthread_assert_true(isc_time_compare(&llim, &now) <= 0);
+	subthread_assert_true(isc_time_compare(&ulim, &now) >= 0);
 
-	assert_int_equal(event->ev_type, ISC_TIMEREVENT_IDLE);
+	isc_interval_set(&interval, 0, 0);
+	isc_mutex_lock(&lasttime_mx);
+	isc_time_add(&now, &interval, &lasttime);
+	isc_mutex_unlock(&lasttime_mx);
+
+	subthread_assert_int_equal(event->ev_type, ISC_TIMEREVENT_IDLE);
 
 	isc_timer_detach(&timer);
 	isc_task_shutdown(task);
@@ -322,41 +373,46 @@ test_reset(isc_task_t *task, isc_event_t *event) {
 	 */
 
 	result = isc_time_now(&now);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, seconds, nanoseconds);
+	isc_mutex_lock(&lasttime_mx);
 	result = isc_time_add(&lasttime, &interval, &base);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	isc_mutex_unlock(&lasttime_mx);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	isc_interval_set(&interval, FUDGE_SECONDS, FUDGE_NANOSECONDS);
 	result = isc_time_add(&base, &interval, &ulim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 	result = isc_time_subtract(&base, &interval, &llim);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
-	assert_true(isc_time_compare(&llim, &now) <= 0);
-	assert_true(isc_time_compare(&ulim, &now) >= 0);
-	lasttime = now;
+	subthread_assert_true(isc_time_compare(&llim, &now) <= 0);
+	subthread_assert_true(isc_time_compare(&ulim, &now) >= 0);
+
+	isc_interval_set(&interval, 0, 0); isc_mutex_lock(&lasttime_mx);
+	isc_time_add(&now, &interval, &lasttime);
+	isc_mutex_unlock(&lasttime_mx);
 
 	int _eventcnt = atomic_load(&eventcnt);
 
 	if (_eventcnt < 3) {
-		assert_int_equal(event->ev_type, ISC_TIMEREVENT_TICK);
+		subthread_assert_int_equal(event->ev_type, ISC_TIMEREVENT_TICK);
 
 		if (_eventcnt == 2) {
 			isc_interval_set(&interval, seconds, nanoseconds);
 			result = isc_time_nowplusinterval(&expires, &interval);
-			assert_int_equal(result, ISC_R_SUCCESS);
+			subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 			isc_interval_set(&interval, 0, 0);
 			result = isc_timer_reset(timer, isc_timertype_once,
 						 &expires, &interval,
 						 false);
-			assert_int_equal(result, ISC_R_SUCCESS);
+			subthread_assert_result_equal(result, ISC_R_SUCCESS);
 		}
 	} else {
-		assert_int_equal(event->ev_type, ISC_TIMEREVENT_LIFE);
+		subthread_assert_int_equal(event->ev_type, ISC_TIMEREVENT_LIFE);
 
 		isc_timer_detach(&timer);
 		isc_task_shutdown(task);
@@ -433,7 +489,7 @@ tick_event(isc_task_t *task, isc_event_t *event) {
 		isc_interval_set(&interval, seconds, 0);
 		result = isc_timer_reset(tickertimer, isc_timertype_ticker,
 					 &expires, &interval, true);
-		assert_int_equal(result, ISC_R_SUCCESS);
+		subthread_assert_result_equal(result, ISC_R_SUCCESS);
 
 		isc_task_shutdown(task);
 	}
@@ -456,7 +512,7 @@ once_event(isc_task_t *task, isc_event_t *event) {
 	startflag = 1;
 
 	result = isc_condition_broadcast(&cv);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 	UNLOCK(&mx);
 
 	isc_event_free(&event);
@@ -481,7 +537,7 @@ shutdown_purge(isc_task_t *task, isc_event_t *event) {
 	shutdownflag = 1;
 
 	result = isc_condition_signal(&cv);
-	assert_int_equal(result, ISC_R_SUCCESS);
+	subthread_assert_result_equal(result, ISC_R_SUCCESS);
 	UNLOCK(&mx);
 
 	isc_event_free(&event);
@@ -518,7 +574,7 @@ purge(void **state) {
 
 	LOCK(&mx);
 
-	event = isc_event_allocate(mctx, (void *)1 , (isc_eventtype_t)1,
+	event = isc_event_allocate(test_mctx, (void *)1 , (isc_eventtype_t)1,
 				   start_event, NULL, sizeof(*event));
 	assert_non_null(event);
 	isc_task_send(task1, &event);
@@ -554,6 +610,8 @@ purge(void **state) {
 
 	UNLOCK(&mx);
 
+	assert_int_equal(atomic_load(&errcnt), ISC_R_SUCCESS);
+
 	assert_int_equal(atomic_load(&eventcnt), 1);
 
 	isc_timer_detach(&tickertimer);
@@ -566,11 +624,11 @@ purge(void **state) {
 int
 main(int argc, char **argv) {
 	const struct CMUnitTest tests[] = {
-		cmocka_unit_test_setup_teardown(ticker, _setup, _teardown),
-		cmocka_unit_test_setup_teardown(once_life, _setup, _teardown),
-		cmocka_unit_test_setup_teardown(once_idle, _setup, _teardown),
-		cmocka_unit_test_setup_teardown(reset, _setup, _teardown),
-		cmocka_unit_test_setup_teardown(purge, _setup, _teardown),
+		cmocka_unit_test(ticker),
+		cmocka_unit_test(once_life),
+		cmocka_unit_test(once_idle),
+		cmocka_unit_test(reset),
+		cmocka_unit_test(purge),
 	};
 	int c;
 
@@ -584,7 +642,7 @@ main(int argc, char **argv) {
 		}
 	}
 
-	return (cmocka_run_group_tests(tests, NULL, NULL));
+	return (cmocka_run_group_tests(tests, _setup, _teardown));
 }
 
 #else /* HAVE_CMOCKA */