From b3feeea385be61b48bc444aae5749ca359a9267e Mon Sep 17 00:00:00 2001
From: Christopher Haster <geky@geky.net>
Date: Wed, 22 May 2024 12:42:07 -0500
Subject: [PATCH] Adopted DENSITY param in test_dirs fuzz tests

Originally implemented in test_files, the DENSITY param sort of squishes
the files/dirs together, so random fuzzing is more likely to end up with
mkdir/rename collisions. These can be a bit more interesting for finding
weird corner cases.
---
 tests/test_dirs.toml | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/tests/test_dirs.toml b/tests/test_dirs.toml
index c67c97cd..ca825260 100644
--- a/tests/test_dirs.toml
+++ b/tests/test_dirs.toml
@@ -1278,6 +1278,8 @@ code = '''
 
 [cases.test_dirs_mkdir_fuzz]
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
+# do more ops than dirs to encourage rename collisions
+defines.DENSITY = 2
 defines.PARENT = [false, true]
 defines.REMOUNT = [false, true]
 defines.SEED = 'range(20)'
@@ -1304,8 +1306,8 @@ code = '''
 
     uint32_t prng = SEED;
     for (lfs_size_t i = 0; i < N; i++) {
-        // choose a pseudo-random number, truncate to 3 hexadecimals
-        lfs_size_t x = TEST_PRNG(&prng) % 0x1000;
+        // choose a pseudo-random number
+        lfs_size_t x = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
 
         // insert into our sim
         for (lfs_size_t j = 0;; j++) {
@@ -4201,6 +4203,8 @@ code = '''
 
 [cases.test_dirs_rm_fuzz]
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
+# do more ops than dirs to encourage rename collisions
+defines.DENSITY = 2
 defines.PARENT = [false, true]
 defines.REMOUNT = [false, true]
 defines.SEED = 'range(20)'
@@ -4231,8 +4235,8 @@ code = '''
         uint8_t op = TEST_PRNG(&prng) % 2;
 
         if (op == 0 || sim_size == 0) {
-            // choose a pseudo-random number, truncate to 3 hexadecimals
-            lfs_size_t x = TEST_PRNG(&prng) % 0x1000;
+            // choose a pseudo-random number
+            lfs_size_t x = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
             // insert into our sim
             for (lfs_size_t j = 0;; j++) {
                 if (j >= sim_size || sim[j] >= x) {
@@ -6669,6 +6673,8 @@ code = '''
 
 [cases.test_dirs_mv_fuzz]
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
+# do more ops than dirs to encourage rename collisions
+defines.DENSITY = 2
 defines.PARENT = [false, true]
 defines.REMOUNT = [false, true]
 defines.SEED = 'range(20)'
@@ -6699,8 +6705,8 @@ code = '''
         uint8_t op = TEST_PRNG(&prng) % 2;
 
         if (op == 0 || sim_size == 0) {
-            // choose a pseudo-random number, truncate to 3 hexadecimals
-            lfs_size_t x = TEST_PRNG(&prng) % 0x1000;
+            // choose a pseudo-random number
+            lfs_size_t x = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
             // insert into our sim
             for (lfs_size_t j = 0;; j++) {
                 if (j >= sim_size || sim[j] >= x) {
@@ -6729,7 +6735,7 @@ code = '''
             // number to rename to
             lfs_size_t j = TEST_PRNG(&prng) % sim_size;
             lfs_size_t x = sim[j];
-            lfs_size_t y = TEST_PRNG(&prng) % 0x1000;
+            lfs_size_t y = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
             for (lfs_size_t k = 0;; k++) {
                 if (k >= sim_size || sim[k] >= y) {
                     // already seen and not a noop?
@@ -6814,6 +6820,8 @@ code = '''
 # test all of the operations together
 [cases.test_dirs_general_fuzz]
 defines.N = [1, 2, 4, 8, 16, 32, 64, 128, 256, 512]
+# do more ops than dirs to encourage rename collisions
+defines.DENSITY = 2
 defines.PARENT = [false, true]
 defines.REMOUNT = [false, true]
 defines.SEED = 'range(20)'
@@ -6844,8 +6852,8 @@ code = '''
         uint8_t op = TEST_PRNG(&prng) % 3;
 
         if (op == 0 || sim_size == 0) {
-            // choose a pseudo-random number, truncate to 3 hexadecimals
-            lfs_size_t x = TEST_PRNG(&prng) % 0x1000;
+            // choose a pseudo-random number
+            lfs_size_t x = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
             // insert into our sim
             for (lfs_size_t j = 0;; j++) {
                 if (j >= sim_size || sim[j] >= x) {
@@ -6888,7 +6896,7 @@ code = '''
             // number to rename to
             lfs_size_t j = TEST_PRNG(&prng) % sim_size;
             lfs_size_t x = sim[j];
-            lfs_size_t y = TEST_PRNG(&prng) % 0x1000;
+            lfs_size_t y = TEST_PRNG(&prng) % ((N+DENSITY-1) / DENSITY);
             for (lfs_size_t k = 0;; k++) {
                 if (k >= sim_size || sim[k] >= y) {
                     // already seen and not a noop?