diff --git a/tests/zfs-tests/include/libtest.shlib b/tests/zfs-tests/include/libtest.shlib
index 7e9dd52f11..e2274d1b17 100644
--- a/tests/zfs-tests/include/libtest.shlib
+++ b/tests/zfs-tests/include/libtest.shlib
@@ -3349,15 +3349,6 @@ function get_min
 	echo $min
 }
 
-#
-# Generate a random number between 1 and the argument.
-#
-function random
-{
-        typeset max=$1
-        echo $(( ($RANDOM % $max) + 1 ))
-}
-
 # Write data that can be compressed into a directory
 function write_compressible
 {
diff --git a/tests/zfs-tests/include/math.shlib b/tests/zfs-tests/include/math.shlib
index 0c3508ec2f..692a2a45ba 100644
--- a/tests/zfs-tests/include/math.shlib
+++ b/tests/zfs-tests/include/math.shlib
@@ -119,3 +119,25 @@ function verify_ne # <a> <b> <type>
 		log_fail "Compared $type should be not equal: $a == $b"
 	fi
 }
+
+# A simple function to get a random number between two bounds (inclusive)
+#
+# Probably not the most efficient for large ranges, but it's okay.
+#
+# Note since we're using $RANDOM, 32767 is the largest number we
+# can accept as the upper bound.
+#
+# $1 lower bound
+# $2 upper bound
+function random_int_between
+{
+	typeset -i min=$1
+	typeset -i max=$2
+	typeset -i rand=0
+
+	while [[ $rand -lt $min ]] ; do
+		rand=$(( $RANDOM % $max + 1))
+	done
+
+	echo $rand
+}
diff --git a/tests/zfs-tests/tests/functional/cli_root/zfs_diff/zfs_diff_timestamp.ksh b/tests/zfs-tests/tests/functional/cli_root/zfs_diff/zfs_diff_timestamp.ksh
index 5efaff8cd5..a4cedca49c 100755
--- a/tests/zfs-tests/tests/functional/cli_root/zfs_diff/zfs_diff_timestamp.ksh
+++ b/tests/zfs-tests/tests/functional/cli_root/zfs_diff/zfs_diff_timestamp.ksh
@@ -50,7 +50,7 @@ function create_random # <fspath> <count>
 
 	while (( i < count )); do
 		log_must touch "$fspath/file$i"
-		sleep $(random 3)
+		sleep $(random_int_between 1 3)
 		(( i = i + 1 ))
 	done
 }
diff --git a/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade.kshlib b/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade.kshlib
index 7b018da1b6..783ae54e71 100644
--- a/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade.kshlib
+++ b/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade.kshlib
@@ -138,22 +138,3 @@ function check_poolversion
 		log_fail "$pool: zpool reported version $actual, expected $vers"
 	fi
 }
-
-# A simple function to get a random number between two bounds
-# probably not the most efficient for large ranges, but it's okay.
-# Note since we're using $RANDOM, 32767 is the largest number we
-# can accept as the upper bound.
-# $1 lower bound
-# $2 upper bound
-function random
-{
-	typeset min=$1
-	typeset max=$2
-	typeset rand=0
-
-	while [[ $rand -lt $min ]] ; do
-		rand=$(( $RANDOM % $max + 1))
-	done
-
-	echo $rand
-}
diff --git a/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade_008_pos.ksh b/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade_008_pos.ksh
index 173d7f68c8..d930919652 100755
--- a/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade_008_pos.ksh
+++ b/tests/zfs-tests/tests/functional/cli_root/zpool_upgrade/zpool_upgrade_008_pos.ksh
@@ -30,6 +30,7 @@
 # Copyright 2015 Nexenta Systems, Inc.  All rights reserved.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/cli_root/zpool_upgrade/zpool_upgrade.kshlib
 
 #
@@ -67,7 +68,7 @@ MAX_VER=15
 
 for ver_old in $VERSIONS; do
 	typeset -n pool_name=ZPOOL_VERSION_${ver_old}_NAME
-	typeset ver_new=$(random $ver_old $MAX_VER)
+	typeset -i ver_new=$(random_int_between $ver_old $MAX_VER)
 
 	create_old_pool $ver_old
 	log_must zpool upgrade -V $ver_new $pool_name > /dev/null
diff --git a/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib b/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
index d3d219bb9b..5150ec5d8b 100644
--- a/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
+++ b/tests/zfs-tests/tests/functional/redacted_send/redacted.kshlib
@@ -100,7 +100,7 @@ function setup_holes
 	log_must zfs create $sendfs/manyrm
 	for i in {1..256}; do
 		log_must stride_dd -i /dev/urandom -o $mntpnt/manyrm/f$i -b 512 \
-		    -c $(random 100) -s $(random 4)
+		    -c $(random_int_between 1 100) -s $(random_int_between 1 4)
 	done
 
 	log_must zfs snapshot $sendfs/manyrm@snap
diff --git a/tests/zfs-tests/tests/functional/redundancy/redundancy_001_pos.ksh b/tests/zfs-tests/tests/functional/redundancy/redundancy_001_pos.ksh
index b5557f1f7e..90d14f6001 100755
--- a/tests/zfs-tests/tests/functional/redundancy/redundancy_001_pos.ksh
+++ b/tests/zfs-tests/tests/functional/redundancy/redundancy_001_pos.ksh
@@ -29,6 +29,7 @@
 # Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/redundancy/redundancy.kshlib
 
 #
@@ -50,7 +51,7 @@ verify_runnable "global"
 log_assert "Verify raidz pool can withstand one device is failing."
 log_onexit cleanup
 
-typeset -i cnt=$(random 2 5)
+typeset -i cnt=$(random_int_between 2 5)
 setup_test_env $TESTPOOL raidz $cnt
 
 #
diff --git a/tests/zfs-tests/tests/functional/redundancy/redundancy_002_pos.ksh b/tests/zfs-tests/tests/functional/redundancy/redundancy_002_pos.ksh
index b16687dbe8..74bda19990 100755
--- a/tests/zfs-tests/tests/functional/redundancy/redundancy_002_pos.ksh
+++ b/tests/zfs-tests/tests/functional/redundancy/redundancy_002_pos.ksh
@@ -29,6 +29,7 @@
 # Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/redundancy/redundancy.kshlib
 
 #
@@ -50,7 +51,7 @@ verify_runnable "global"
 log_assert "Verify raidz2 pool can withstand two devices are failing."
 log_onexit cleanup
 
-typeset -i cnt=$(random 3 5)
+typeset -i cnt=$(random_int_between 3 5)
 setup_test_env $TESTPOOL raidz2 $cnt
 
 #
diff --git a/tests/zfs-tests/tests/functional/redundancy/redundancy_003_pos.ksh b/tests/zfs-tests/tests/functional/redundancy/redundancy_003_pos.ksh
index a1ca2cb765..b7b791b248 100755
--- a/tests/zfs-tests/tests/functional/redundancy/redundancy_003_pos.ksh
+++ b/tests/zfs-tests/tests/functional/redundancy/redundancy_003_pos.ksh
@@ -29,6 +29,7 @@
 # Copyright (c) 2013 by Delphix. All rights reserved.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/redundancy/redundancy.kshlib
 
 #
@@ -50,7 +51,7 @@ verify_runnable "global"
 log_assert "Verify mirrored pool can withstand N-1 devices are failing or missing."
 log_onexit cleanup
 
-typeset -i cnt=$(random 2 5)
+typeset -i cnt=$(random_int_between 2 5)
 setup_test_env $TESTPOOL mirror $cnt
 
 typeset -i i=1
diff --git a/tests/zfs-tests/tests/functional/redundancy/redundancy_004_neg.ksh b/tests/zfs-tests/tests/functional/redundancy/redundancy_004_neg.ksh
index cb4603af80..7ee51051ea 100755
--- a/tests/zfs-tests/tests/functional/redundancy/redundancy_004_neg.ksh
+++ b/tests/zfs-tests/tests/functional/redundancy/redundancy_004_neg.ksh
@@ -29,6 +29,7 @@
 # Copyright (c) 2013, 2016 by Delphix. All rights reserved.
 #
 
+. $STF_SUITE/include/libtest.shlib
 . $STF_SUITE/tests/functional/redundancy/redundancy.kshlib
 
 #
@@ -50,7 +51,7 @@ verify_runnable "global"
 log_assert "Verify striped pool have no data redundancy."
 log_onexit cleanup
 
-typeset -i cnt=$(random 2 5)
+typeset -i cnt=$(random_int_between 2 5)
 setup_test_env $TESTPOOL "" $cnt
 
 damage_devs $TESTPOOL 1 "keep_label"