test: Add negative cache system test

Signed-off-by: Anton Jastsuk <antonjastsuk66@gmail.com>

Author: ZaRdEr15

tests/test_suites/ShortSystemTests/test_negative_cache.sh

@@ -0,0 +1,48 @@
+timeout_set 40 seconds
+MOUNT_EXTRA_CONFIG="sfsnegativecachesize=4,sfsnegativecachetimeout=9000" \
+	USE_RAMDISK=YES \
+	setup_local_empty_saunafs info
+
+cd ${info[mount0]}
+
+# Tweaks test
+expect_equals "9000" "$(cat ${info[mount0]}/.saunafs_tweaks | awk 'BEGIN{IGNORECASE=1} /negativecachetimeout/ {print $2}')"
+expect_equals "4" "$(cat ${info[mount0]}/.saunafs_tweaks | awk 'BEGIN{IGNORECASE=1} /negativecachemaxsize/ {print $2}')"
+
+echo "NegativeCacheTimeout=9001" | sudo tee ${info[mount0]}/.saunafs_tweaks
+echo "NegativeCacheMaxSize=5" | sudo tee ${info[mount0]}/.saunafs_tweaks
+
+expect_equals "9001" "$(cat ${info[mount0]}/.saunafs_tweaks | awk 'BEGIN{IGNORECASE=1} /negativecachetimeout/ {print $2}')"
+expect_equals "5" "$(cat ${info[mount0]}/.saunafs_tweaks | awk 'BEGIN{IGNORECASE=1} /negativecachemaxsize/ {print $2}')"
+
+# Timeout test
+test_file=nonexistent_file
+assert_failure ls ${test_file}
+
+touch ${test_file}
+assert_failure ls ${test_file}
+
+assert_eventually "ls ${test_file}" "20 seconds"
+
+# LRU eviction test, remove oldest when exceeds max size
+files1=({a..f}) # 6 files
+
+# When file f is added, a is removed because it is oldest
+for file in ${files1[@]}; do assert_failure ls ${file}; done
+touch ${files1[0]}
+assert_success ls ${files1[0]}
+
+# Tweaks change clears whole cache
+files2=({A..C})
+for file in ${files2[@]}; do assert_failure ls ${file}; done
+echo "NegativeCacheTimeout=9000" | sudo tee ${info[mount0]}/.saunafs_tweaks
+assert_failure ls D # clears caches
+touch ${files2[@]}
+for file in ${files2[@]}; do assert_success ls ${file}; done
+rm ${files2[@]}
+
+for file in ${files2[@]}; do assert_failure ls ${file}; done
+echo "NegativeCacheMaxSize=4" | sudo tee ${info[mount0]}/.saunafs_tweaks
+assert_failure ls E # clears caches
+touch ${files2[@]}
+for file in ${files2[@]}; do assert_success ls ${file}; done