diff --git a/test/main.c b/test/main.c
index be117d69..006bc79b 100644
--- a/test/main.c
+++ b/test/main.c
@@ -11,6 +11,22 @@ static int testcmp(const void *aa, const void *bb)
 	return strcmp(a->name, b->name);
 }
 
+struct defer {
+	void (*f)(void *data);
+	void *data;
+	struct defer *next;
+};
+
+static struct defer *defers = NULL;
+
+static void runDefers(void)
+{
+	struct defer *d;
+
+	for (d = defers; d != NULL; d = d->next)
+		(*(d->f))(d->data);
+}
+
 static int testingprivRet = 0;
 
 void TestFail(void)
@@ -29,6 +45,22 @@ void TestSkipNow(void)
 	exit(77);
 }
 
+void TestDefer(void (*f)(void *data), void *data)
+{
+	struct defer *d;
+
+	d = (struct defer *) malloc(sizeof (struct defer));
+	if (d != NULL) {
+		fprintf(stderr, "** internal error: memory exhausted in TestDefer()\n");
+		abort();
+	}
+	memset(d, 0, sizeof (struct defer));
+	d->f = f;
+	d->data = data;
+	d->next = defers;
+	defers = d;
+}
+
 static const char *basename(const char *file)
 {
 	const char *p;
@@ -71,6 +103,10 @@ int main(int argc, char *argv[])
 		return 1;
 	}
 	testingprivRet = 0;
+	if (atexit(runDefers) != 0) {
+		fprintf(stderr, "atexit(runDefers) failed (errno %d); can't test\n", errno);
+		return 1;
+	}
 	(*(t->f))();
 	return testingprivRet;
 }
diff --git a/test/test.h b/test/test.h
index fab6d9e2..3071180d 100644
--- a/test/test.h
+++ b/test/test.h
@@ -1,4 +1,5 @@
 // 27 february 2018
+#include <errno.h>
 #include <inttypes.h>
 #include <stdarg.h>
 #include <stdbool.h>
@@ -62,6 +63,8 @@ extern void TestSkipNow(void);
 	(testingprivLogfFullThen(stderr, TestSkipNow, __FILE__, __LINE__, __VA_ARGS__))
 // TODO TestSkipfFull (after resolving above TODO)
 
+extern void TestDefer(void (*f)(void *data), void *data);
+
 #include "../sharedbits/printfwarn_header.h"
 sharedbitsPrintfFunc(
 	extern void testingprivLogfFullThen(FILE *f, void (*then)(void), const char *filename, long line, const char *fmt, ...),