diff --git a/fixtures/test-expiring-file-upload/test.sh b/fixtures/test-expiring-file-upload/test.sh
index a05eeae..c998c00 100755
--- a/fixtures/test-expiring-file-upload/test.sh
+++ b/fixtures/test-expiring-file-upload/test.sh
@@ -9,7 +9,7 @@ setup() {
 run_test() {
   file_url=$(curl -s -F "file=@file" -H "expire:1s" localhost:8000)
   test "$content" = "$(cat upload/file.txt.*)"
-  sleep 2s
+  sleep 2
 
   result="$(curl -s $file_url)"
   test "file is not found or expired :(" = "$result"
diff --git a/fixtures/test-list-files/test.sh b/fixtures/test-list-files/test.sh
index 1cdc2fd..a76c7ab 100755
--- a/fixtures/test-list-files/test.sh
+++ b/fixtures/test-list-files/test.sh
@@ -10,7 +10,7 @@ setup() {
 
 run_test() {
   seq $file_count | xargs -I -- curl -s -F "file=@file" -H "Authorization: $auth_token" localhost:8000 >/dev/null
-  test "$file_count" = "$(curl -s -H "Authorization: $auth_token" localhost:8000/list | grep -o 'file_name' | wc -l)"
+  test $file_count = $(curl -s -H "Authorization: $auth_token" localhost:8000/list | grep -o 'file_name' | wc -l)
   test "unauthorized" = "$(curl -s localhost:8000/list)"
 }
 
diff --git a/fixtures/test-server-auto-deletion/test.sh b/fixtures/test-server-auto-deletion/test.sh
index 3065ac6..5fc2ef4 100755
--- a/fixtures/test-server-auto-deletion/test.sh
+++ b/fixtures/test-server-auto-deletion/test.sh
@@ -11,10 +11,10 @@ run_test() {
   second_file_url=$(curl -s -F "file=@file" -H "expire:4s" localhost:8000)
   test "$content" = "$(curl -s $first_file_url)"
   test "$content" = "$(curl -s $second_file_url)"
-  sleep 3s
+  sleep 3
   test "file is not found or expired :(" = "$(curl -s $first_file_url)"
   test "$content" = "$(curl -s $second_file_url)"
-  sleep 1s
+  sleep 1
   test "file is not found or expired :(" = "$(curl -s $second_file_url)"
 }
 
diff --git a/fixtures/test-server-payload-limit/test.sh b/fixtures/test-server-payload-limit/test.sh
index 07399f3..8527578 100755
--- a/fixtures/test-server-payload-limit/test.sh
+++ b/fixtures/test-server-payload-limit/test.sh
@@ -3,7 +3,8 @@
 setup() {
   touch emptyfile
   truncate -s 9KB smallfile
-  fallocate -l 10000 normalfile
+  # On Linux, `fallocate -l 10000 normalfile` can be used for a better precision.
+  dd if=/dev/random of=normalfile count=10000 bs=1024 status=none
   truncate -s 11KB bigfile
 }