intmap: add exhaustive testcases for intmap_after

We can't do the full range, but we can for a handful of bits (8).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/intmap/test/run-after-exhaustive.c b/ccan/intmap/test/run-after-exhaustive.c
new file mode 100644 (file)
index 0000000..1655ddb
--- /dev/null
+++ b/ccan/intmap/test/run-after-exhaustive.c
@@ -0,0 +1,41 @@
+#include <ccan/bitops/bitops.h>
+#include <ccan/intmap/intmap.c>
+#include <ccan/tap/tap.h>
+#include <stdio.h>
+
+#define ELEMENTS 8
+
+int main(void)
+{
+       UINTMAP(void *) umap;
+
+       plan_tests((1 << ELEMENTS) * ELEMENTS);
+
+       /* Run through every combination of elements */
+       for (int i = 0; i < (1 << ELEMENTS); i++) {
+               /* Set up map */
+               uintmap_init(&umap);
+               for (int j = 0; j < ELEMENTS; j++) {
+                       if ((1 << j) & i)
+                               uintmap_add(&umap, j, &umap);
+               }
+
+               /* Try each uintmap_after value */
+               for (int j = 0; j < ELEMENTS; j++) {
+                       intmap_index_t idx = j, next;
+
+                       if ((i >> (j + 1)) == 0)
+                               next = 0;
+                       else
+                               next = j + 1 + bitops_ls32(i >> (j + 1));
+
+                       if (!uintmap_after(&umap, &idx))
+                               idx = 0;
+                       ok1(idx == next);
+               }
+               uintmap_clear(&umap);
+       }
+
+       /* This exits depending on whether all tests passed */
+       return exit_status();
+}