From 1108191184df488d57e04892eff705ac407abe35 Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Wed, 28 Dec 2022 00:58:59 -0600
Subject: [PATCH] Added permutation testing of rbyd lookups over multiple
 commits

In theory spreading rbyd trees across multiple commits shouldn't change
anything, but the whole point of testing is to catch things that are not
in the theory.
---
 tests/test_rbyd.toml | 78 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

diff --git a/tests/test_rbyd.toml b/tests/test_rbyd.toml
index 034cbba7..4e7029fc 100644
--- a/tests/test_rbyd.toml
+++ b/tests/test_rbyd.toml
@@ -1486,3 +1486,81 @@ code = '''
         }
     }
 '''
+
+[cases.test_rbyd_multi_permutations]
+defines.N = 'range(1, 8)'
+in = 'lfs.c'
+code = '''
+    lfs_t lfs;
+    lfs_init(&lfs, cfg) => 0;
+
+    lfs_rbyd_t rbyd_init = {
+        .block = 0,
+        .trunk = 0,
+        .noff = 0,
+        .rev = 1,
+        .crc = 0,
+        .count = 0,
+        .erased = true,
+    };
+    lfs_rbyd_t rbyd;
+    lfs_off_t off;
+    lfs_size_t size;
+
+    // test all permutations of a given size
+    uint8_t perm[N];
+    uint8_t stack[N];
+    for (uint8_t i = 0; i < N; i++) {
+        perm[i] = i;
+        stack[i] = 0;
+    }
+
+    uint8_t i = 1;
+    while (i < N) {
+        // print permutation to help debugging
+        printf("--- permutation: [");
+        for (int j = 0; j < N; j++) {
+            if (j > 0) {
+                printf(", ");
+            }
+            printf("%d", perm[j]+1);
+        }
+        printf("] ---\n");
+
+        // test the given permutation with multiple commits
+        rbyd = rbyd_init;
+        lfs_bd_erase(&lfs, rbyd.block) => 0;
+
+        for (int j = 0; j < N; j++) {
+            lfs_rbyd_commit(&lfs, &rbyd,
+                    LFS_MKRATTR(
+                        UATTR, perm[j]+1, 0,
+                        &(uint32_t){0xaaaaaaaa}, 4, NULL)) => 0;
+        }
+
+        lfs_rbyd_fetch(&lfs, &rbyd, rbyd.block, NULL) => 0;
+        for (int j = 0; j < N; j++) {
+            lfs_rbyd_lookup(&lfs, &rbyd,
+                    LFS_MKRTAG(UATTR, j+1, 0), &off, &size)
+                    => LFS_MKRTAG(UATTR, j+1, 0);
+        }
+
+        // next permutation using Heap's algorithm
+        if (stack[i] < i) {
+            if (i % 2 == 0) {
+                uint8_t t = perm[0];
+                perm[0] = perm[i];
+                perm[i] = t;
+            } else {
+                uint8_t t = perm[stack[i]];
+                perm[stack[i]] = perm[i];
+                perm[i] = t;
+            }
+            stack[i] += 1;
+            i = 1;
+        } else {
+            stack[i] = 0;
+            i += 1;
+        }
+    }
+'''