Write a small set of unit tests aiming for high coverage

These currently cover most reachable lines and branches, except the
case where malloc fails in timeouts_open(), the if() branch in
timeouts_readd() (see issue #7) , and some failure cases in
timeouts_check().

Makefile

-all: bench bench-wheel.so bench-heap.so
+all: bench bench-wheel.so bench-heap.so test-timeout
 
 WHEEL_BIT = 6
 WHEEL_NUM = 4
@@ -27,6 +27,8 @@ timeout.o: timeout.c
 bench: bench.c timeout.h
 	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $< -ldl
 
+test-timeout: timeout.o test-timeout.o
+	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ timeout.o test-timeout.o
 
 ifeq ($(shell uname -s), Darwin)
 SOFLAGS = -bundle -undefined dynamic_lookup

test-timeout.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <limits.h>
+
+#include "timeout.h"
+
+#define THE_END_OF_TIME ((timeout_t)-1)
+
+static int check_misc(void) {
+	if (TIMEOUT_VERSION != timeout_version())
+		return 1;
+	if (TIMEOUT_V_REL != timeout_v_rel())
+		return 1;
+	if (TIMEOUT_V_API != timeout_v_api())
+		return 1;
+	if (TIMEOUT_V_ABI != timeout_v_abi())
+		return 1;
+	if (strcmp(timeout_vendor(), TIMEOUT_VENDOR))
+		return 1;
+	return 0;
+}
+
+static int check_open_close(timeout_t hz_set, timeout_t hz_expect) {
+	int err=0;
+	struct timeouts *tos = timeouts_open(hz_set, &err);
+	if (!tos)
+		return 1;
+	if (err)
+		return 1;
+	if (hz_expect != timeouts_hz(tos))
+		return 1;
+	timeouts_close(tos);
+	return 0;
+}
+
+/* Not very random */
+static timeout_t random_to(timeout_t min, timeout_t max)
+{
+	if (max <= min)
+		return min;
+	/* Not actually all that random, but should exercise the code. */
+	timeout_t rand64 = random() * (timeout_t)INT_MAX + random();
+	return min + (rand64 % (max-min));
+}
+
+/* configuration for check_randomized */
+struct rand_cfg {
+	/* When creating timeouts, smallest possible delay */
+	timeout_t min_timeout;
+	/* When creating timeouts, largest possible delay */
+	timeout_t max_timeout;
+	/* First time to start the clock at. */
+	timeout_t start_at;
+	/* Do not advance the clock past this time. */
+	timeout_t end_at;
+	/* Number of timeouts to create and monitor. */
+	int n_timeouts;
+	/* Advance the clock by no more than this each step. */
+	timeout_t max_step;
+	/* Use relative timers and stepping */
+	int relative;
+	/* Every time the clock ticks, try removing this many timeouts at
+	 * random. */
+	int try_removing;
+	/* When we're done, advance the clock to the end of time. */
+	int finalize;
+};
+
+static int check_randomized(const struct rand_cfg *cfg)
+{
+#define FAIL() do {					\
+		printf("Failure on line %d\n", __LINE__);	\
+		goto done;					\
+	} while (0)
+
+	int i, err;
+	int rv = 1;
+	struct timeout *t = calloc(cfg->n_timeouts, sizeof(struct timeout));
+	timeout_t *timeouts = calloc(cfg->n_timeouts, sizeof(timeout_t));
+	uint8_t *fired = calloc(cfg->n_timeouts, sizeof(uint8_t));
+	uint8_t *deleted = calloc(cfg->n_timeouts, sizeof(uint8_t));
+	struct timeouts *tos = timeouts_open(0, &err);
+	timeout_t now = cfg->start_at;
+	int n_added_pending = 0;
+	int n_added_expired = 0;
+	struct timeout *to = NULL;
+	const int rel = cfg->relative;
+
+	if (!t || !timeouts || !tos || !fired || !deleted)
+		FAIL();
+	timeouts_update(tos, cfg->start_at);
+
+	for (i = 0; i < cfg->n_timeouts; ++i) {
+		if (&t[i] != timeout_init(&t[i], rel ? 0 : TIMEOUT_ABS))
+			FAIL();
+		if (timeout_pending(&t[i]))
+			FAIL();
+		if (timeout_expired(&t[i]))
+			FAIL();
+
+		timeouts[i] = random_to(cfg->min_timeout, cfg->max_timeout);
+
+		timeouts_add(tos, &t[i], timeouts[i] - (rel ? now : 0));
+		if (timeouts[i] <= cfg->start_at) {
+			if (timeout_pending(&t[i]))
+				FAIL();
+			if (! timeout_expired(&t[i]))
+				FAIL();
+			++n_added_expired;
+		} else {
+			if (! timeout_pending(&t[i]))
+				FAIL();
+			if (timeout_expired(&t[i]))
+				FAIL();
+			++n_added_pending;
+		}
+	}
+
+	if (!!n_added_pending != timeouts_pending(tos))
+		FAIL();
+	if (!!n_added_expired != timeouts_expired(tos))
+		FAIL();
+
+	while (NULL != (to = timeouts_get(tos))) {
+		i = to - &t[0];
+		assert(&t[i] == to);
+		if (timeouts[i] > cfg->start_at)
+			FAIL(); /* shouldn't have happened yet */
+
+		--n_added_expired; /* drop expired timeouts. */
+		++fired[i];
+	}
+
+	if (n_added_expired != 0)
+		FAIL();
+
+	while (now < cfg->end_at) {
+		int n_fired_this_time = 0;
+		timeout_t first_at = timeouts_timeout(tos) + now;
+
+		timeout_t oldtime = now;
+		timeout_t step = random_to(1, cfg->max_step);
+		int another;
+		now += step;
+		if (rel)
+			timeouts_step(tos, step);
+		else
+			timeouts_update(tos, now);
+
+		for (i = 0; i < cfg->try_removing; ++i) {
+			int idx = random() % cfg->n_timeouts;
+			if (! fired[idx]) {
+				timeout_del(&t[idx]);
+				++deleted[idx];
+			}
+		}
+
+		another = (timeouts_timeout(tos) == 0);
+
+		while (NULL != (to = timeouts_get(tos))) {
+			if (! another)
+				FAIL(); /* Thought we saw the last one! */
+			i = to - &t[0];
+			assert(&t[i] == to);
+			if (timeouts[i] > now)
+				FAIL(); /* shouldn't have happened yet */
+			if (timeouts[i] <= oldtime)
+				FAIL(); /* should have happened already */
+			if (timeouts[i] < first_at)
+				FAIL(); /* first_at should've been earlier */
+			fired[i]++;
+			n_fired_this_time++;
+			another = (timeouts_timeout(tos) == 0);
+		}
+		if (n_fired_this_time && first_at > now)
+			FAIL(); /* first_at should've been earlier */
+		if (another)
+			FAIL(); /* Huh? We think there are more? */
+		if (!timeouts_check(tos, stderr))
+			FAIL();
+	}
+
+	for (i = 0; i < cfg->n_timeouts; ++i) {
+		if (fired[i] > 1)
+			FAIL(); /* Nothing fired twice. */
+		if (timeouts[i] <= now) {
+			if (!(fired[i] || deleted[i]))
+				FAIL();
+		} else {
+			if (fired[i])
+				FAIL();
+		}
+		if (fired[i] && deleted[i])
+			FAIL();
+		if (cfg->finalize > 1) {
+			if (!fired[i])
+				timeout_del(&t[i]);
+		}
+	}
+
+	/* Now nothing more should fire between now and the end of time. */
+	if (cfg->finalize) {
+		timeouts_update(tos, THE_END_OF_TIME);
+		if (cfg->finalize > 1) {
+			if (timeouts_get(tos))
+				FAIL();
+		}
+	}
+	rv = 0;
+
+ done:
+	if (t) free(t);
+	if (timeouts) free(timeouts);
+	if (tos) timeouts_close(tos);
+	if (fired) free(fired);
+	if (deleted) free(deleted);
+	return rv;
+}
+
+struct intervals_cfg {
+	const timeout_t *timeouts;
+	int n_timeouts;
+	timeout_t start_at;
+	timeout_t end_at;
+};
+
+int
+check_intervals(struct intervals_cfg *cfg)
+{
+	int i, err;
+	int rv = 1;
+	struct timeout *to;
+	struct timeout *t = calloc(cfg->n_timeouts, sizeof(struct timeout));
+	unsigned *fired = calloc(cfg->n_timeouts, sizeof(unsigned));
+	struct timeouts *tos = timeouts_open(0, &err);
+
+	timeout_t now = cfg->start_at;
+	if (!t || !tos || !fired)
+		FAIL();
+
+	timeouts_update(tos, now);
+
+	for (i = 0; i < cfg->n_timeouts; ++i) {
+		if (&t[i] != timeout_init(&t[i], TIMEOUT_INT))
+			FAIL();
+		if (timeout_pending(&t[i]))
+			FAIL();
+		if (timeout_expired(&t[i]))
+			FAIL();
+
+		timeouts_add(tos, &t[i], cfg->timeouts[i]);
+		if (! timeout_pending(&t[i]))
+			FAIL();
+		if (timeout_expired(&t[i]))
+			FAIL();
+	}
+
+	while (now < cfg->end_at) {
+		timeout_t delay = timeouts_timeout(tos);
+		timeouts_step(tos, delay);
+
+		now += delay;
+
+		while (NULL != (to = timeouts_get(tos))) {
+			i = to - &t[0];
+			assert(&t[i] == to);
+			fired[i]++;
+		}
+		if (!timeouts_check(tos, stderr))
+			FAIL();
+	}
+
+	timeout_t duration = cfg->end_at - cfg->start_at;
+	for (i = 0; i < cfg->n_timeouts; ++i) {
+		if (fired[i] != duration / cfg->timeouts[i])
+			FAIL();
+		if (!timeout_pending(&t[i]))
+			FAIL();
+	}
+
+	rv = 0;
+ done:
+	if (t) free(t);
+	if (fired) free(fired);
+	if (tos) free(tos);
+	return rv;
+}
+
+int
+main(int argc, char **argv)
+{
+	int j;
+	int n_failed = 0;
+#define DO(fn) do {                             \
+		printf("."); fflush(stdout);	\
+		if (fn) {			\
+			++n_failed;		\
+			printf("%s failed\n", #fn);	\
+		}					\
+        } while (0)
+
+#define DO_N(n, fn) do {			\
+		for (j = 0; j < (n); ++j) {	\
+			DO(fn);			\
+		}				\
+	} while (0)
+
+        DO(check_misc());
+	DO(check_open_close(1000, 1000));
+	DO(check_open_close(0, TIMEOUT_mHZ));
+
+	struct rand_cfg cfg1 = {
+		.min_timeout = 1,
+		.max_timeout = 100,
+		.start_at = 5,
+		.end_at = 1000,
+		.n_timeouts = 1000,
+		.max_step = 10,
+		.relative = 0,
+		.try_removing = 0,
+		.finalize = 2,
+		};
+	DO_N(300,check_randomized(&cfg1));
+
+	struct rand_cfg cfg2 = {
+		.min_timeout = 20,
+		.max_timeout = 1000,
+		.start_at = 10,
+		.end_at = 100,
+		.n_timeouts = 1000,
+		.max_step = 5,
+		.relative = 1,
+		.try_removing = 0,
+		.finalize = 2,
+		};
+	DO_N(300,check_randomized(&cfg2));
+
+	struct rand_cfg cfg2b = {
+		.min_timeout = 20,
+		.max_timeout = 1000,
+		.start_at = 10,
+		.end_at = 100,
+		.n_timeouts = 1000,
+		.max_step = 5,
+		.relative = 1,
+		.try_removing = 0,
+		.finalize = 1,
+		};
+	DO_N(300,check_randomized(&cfg2b));
+
+	struct rand_cfg cfg2c = {
+		.min_timeout = 20,
+		.max_timeout = 1000,
+		.start_at = 10,
+		.end_at = 100,
+		.n_timeouts = 1000,
+		.max_step = 5,
+		.relative = 1,
+		.try_removing = 0,
+		.finalize = 0,
+		};
+	DO_N(300,check_randomized(&cfg2c));
+
+	struct rand_cfg cfg3 = {
+		.min_timeout = 2000,
+		.max_timeout = ((uint64_t)1) << 50,
+		.start_at = 100,
+		.end_at = ((uint64_t)1) << 49,
+		.n_timeouts = 1000,
+		.max_step = 1<<31,
+		.relative = 0,
+		.try_removing = 0,
+		.finalize = 2,
+		};
+	DO_N(10,check_randomized(&cfg3));
+
+	struct rand_cfg cfg3b = {
+		.min_timeout = ((uint64_t)1) << 50,
+		.max_timeout = ((uint64_t)1) << 52,
+		.start_at = 100,
+		.end_at = ((uint64_t)1) << 53,
+		.n_timeouts = 1000,
+		.max_step = ((uint64_t)1)<<48,
+		.relative = 0,
+		.try_removing = 0,
+		.finalize = 2,
+		};
+	DO_N(10,check_randomized(&cfg3b));
+
+	struct rand_cfg cfg4 = {
+		.min_timeout = 2000,
+		.max_timeout = ((uint64_t)1) << 30,
+		.start_at = 100,
+		.end_at = ((uint64_t)1) << 26,
+		.n_timeouts = 10000,
+		.max_step = 1<<16,
+		.relative = 0,
+		.try_removing = 3,
+		.finalize = 2,
+		};
+	DO_N(10,check_randomized(&cfg4));
+
+	const timeout_t primes[] = {
+		2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,
+		59,61,67,71,73,79,83,89,97
+	};
+	const timeout_t factors_of_1337[] = {
+		1, 7, 191, 1337
+	};
+	const timeout_t multiples_of_five[] = {
+		5, 10, 15, 20, 25, 30, 35, 40, 45, 50
+	};
+
+	struct intervals_cfg icfg1 = {
+		.timeouts = primes,
+		.n_timeouts = sizeof(primes)/sizeof(timeout_t),
+		.start_at = 50,
+		.end_at = 5322,
+	};
+	DO(check_intervals(&icfg1));
+
+	struct intervals_cfg icfg2 = {
+		.timeouts = primes,
+		.n_timeouts = sizeof(factors_of_1337)/sizeof(timeout_t),
+		.start_at = 50,
+		.end_at = 50000,
+	};
+	DO(check_intervals(&icfg2));
+
+	struct intervals_cfg icfg3 = {
+		.timeouts = primes,
+		.n_timeouts = sizeof(multiples_of_five)/sizeof(timeout_t),
+		.start_at = 49,
+		.end_at = 5333,
+	};
+	DO(check_intervals(&icfg3));
+
+
+        if (n_failed) {
+          puts("\nFAIL");
+        } else {
+          puts("\nOK");
+        }
+	return !!n_failed;
+}
+
+/* TODO:
+
+ * Solve PR#3.
+
+ * Investigate whether any untaken branches are possible.
+
+ */