1 files changed, 71 insertions, 0 deletions
diff --git a/lib/ccan/tally/test/run-bucket_of.c b/lib/ccan/tally/test/run-bucket_of.c
new file mode 100644
index 00000000000..5e12725757f
--- /dev/null
+++ b/lib/ccan/tally/test/run-bucket_of.c
@@ -0,0 +1,71 @@
+#include <ccan/tally/tally.c>
+#include <ccan/tap/tap.h>
+
+int main(void)
+{
+	unsigned int i, max_step;
+	ssize_t min, max;
+
+	max = (ssize_t)~(1ULL << (sizeof(max)*CHAR_BIT - 1));
+	min = (ssize_t)(1ULL << (sizeof(max)*CHAR_BIT - 1));
+	max_step = sizeof(max)*CHAR_BIT;
+
+	plan_tests(2 + 100 + 10 + 5
+		   + 2 + 100 + 5 + 4
+		   + (1 << 7) * (max_step - 7));
+
+	/* Single step, single bucket == easy. */
+	ok1(bucket_of(0, 0, 0) == 0);
+
+	/* Double step, still in first bucket. */
+	ok1(bucket_of(0, 1, 0) == 0);
+
+	/* Step 8. */
+	for (i = 0; i < 100; i++)
+		ok1(bucket_of(0, 3, i) == i >> 3);
+
+	/* 10 values in 5 buckets, step 2. */
+	for (i = 0; i < 10; i++)
+		ok1(bucket_of(0, 1, i) == i >> 1);
+
+	/* Extreme cases. */
+	ok1(bucket_of(min, 0, min) == 0);
+	ok1(bucket_of(min, max_step-1, min) == 0);
+	ok1(bucket_of(min, max_step-1, max) == 1);
+	ok1(bucket_of(min, max_step, min) == 0);
+	ok1(bucket_of(min, max_step, max) == 0);
+
+	/* Now, bucket_min() should match: */
+	ok1(bucket_min(0, 0, 0) == 0);
+
+	/* Double step, val in first bucket still 0. */
+	ok1(bucket_min(0, 1, 0) == 0);
+
+	/* Step 8. */
+	for (i = 0; i < 100; i++)
+		ok1(bucket_min(0, 3, i) == i << 3);
+
+	/* 10 values in 5 buckets, step 2. */
+	for (i = 0; i < 5; i++)
+		ok1(bucket_min(0, 1, i) == i << 1);
+
+	/* Extreme cases. */
+	ok1(bucket_min(min, 0, 0) == min);
+	ok1(bucket_min(min, max_step-1, 0) == min);
+	ok1(bucket_min(min, max_step-1, 1) == 0);
+	ok1(bucket_min(min, max_step, 0) == min);
+
+	/* Now, vary step and number of buckets, but bucket_min and bucket_of
+	 * must agree. */
+	for (i = 0; i < (1 << 7); i++) {
+		unsigned int j;
+		for (j = 0; j < max_step - 7; j++) {
+			ssize_t val;
+
+			val = bucket_min(-(ssize_t)i, j, i);
+			ok1(bucket_of(-(ssize_t)i, j, val) == i);
+		}
+	}
+
+	return exit_status();
+}