diff --git a/tests/zfs-tests/include/math.shlib b/tests/zfs-tests/include/math.shlib
index 692a2a45ba4b..7ac59f279604 100644
--- a/tests/zfs-tests/include/math.shlib
+++ b/tests/zfs-tests/include/math.shlib
@@ -1,143 +1,144 @@
 #
 # This file and its contents are supplied under the terms of the
 # Common Development and Distribution License ("CDDL"), version 1.0.
 # You may only use this file in accordance with the terms of version
 # 1.0 of the CDDL.
 #
 # A full copy of the text of the CDDL should have accompanied this
 # source.  A copy of the CDDL is also available via the Internet at
 # http://www.illumos.org/license/CDDL.
 #
 
 #
 # Copyright (c) 2012, 2016 by Delphix. All rights reserved.
 #
 
 #
 # Return 0 if the percentage difference between $a and $b is $percent or
 # greater. Return 1 if the percentage is lower or if we would divide by
 # zero. For use like this:
 #
 # Do $action if the calculated percentage is greater or equal to that passed in:
 #	within_percent A B P && $action
 # Do $action if the calculated percentage is less than that passed in:
 #	within_percent A B P || $action
 #
 function within_percent
 {
 	typeset a=$1
 	typeset b=$1
 	typeset percent=$3
 
 	# Set $a or $b to $2 such that a >= b
-	[[ '1' = $(echo "if ($2 > $a) 1" | bc) ]] && a=$2 || b=$2
+	[[ '1' = $(echo "if ($2 > $a) 1 else 0" | bc) ]] && a=$2 || b=$2
 
 	# Prevent division by 0
 	[[ $a =~ [1-9] ]] || return 1
 
 	typeset p=$(echo "scale=2; $b * 100 / $a" | bc)
 	log_note "Comparing $a and $b given $percent% (calculated: $p%)"
-	[[ '1' = $(echo "scale=2; if ($p >= $percent) 1" | bc) ]] && return 0
+	[[ '1' = $(echo "scale=2; if ($p >= $percent) 1 else 0" | bc) ]] && \
+	    return 0
 
 	return 1
 }
 
 #
 # Return 0 if value is within +/-tolerance of target.
 # Return 1 if value exceeds our tolerance.
 # For use like this:
 #
 # Do $action if value is within the tolerance from target passed in:
 #	within_tolerance VAL TAR TOL && $action
 # Do $action if value surpasses the tolerance from target passed in:
 #	within_tolerance VAL TAR TOL || $action
 #
 function within_tolerance #value #target #tolerance
 {
 	typeset val=$1
 	typeset target=$2
 	typeset tol=$3
 
 	typeset diff=$((abs(val - target)))
 	log_note "Checking if $val is within +/-$tol of $target (diff: $diff)"
 	((diff <= tol)) && return 0
 
 	return 1
 }
 
 #
 # Return 0 if the human readable string of the form <value>[suffix] can
 # be converted to bytes.  Allow suffixes are shown in the table below.
 #
 function to_bytes
 {
 	typeset size=$1
 	typeset value=$(echo "$size" | grep -o '[0-9]\+')
 
 	case $size in
 		*PB|*pb|*P|*p)	factor='1024^5'	;;
 		*TB|*tb|*T|*t)	factor='1024^4'	;;
 		*GB|*gb|*G|*g)	factor='1024^3'	;;
 		*MB|*mb|*M|*m)	factor='1024^2'	;;
 		*KB|*kb|*K|*k)	factor='1024^1'	;;
 		*B|*b)		factor='1024^0'	;;
 		*[!0-9.]*)	return 1 ;;
 		*)		factor='1024^0'	;;
 	esac
 
 	echo "$value * ($factor)" | bc
 
 	return 0
 }
 
 #
 # Verify $a is equal to $b, otherwise raise an error specifying
 # the $type of values being compared
 #
 function verify_eq # <a> <b> <type>
 {
 	typeset a=$1
 	typeset b=$2
 	typeset type=$3
 
 	if [[ $a -ne $b ]]; then
 		log_fail "Compared $type should be equal: $a != $b"
 	fi
 }
 
 #
 # Verify $a is not equal to $b, otherwise raise an error specifying
 # the $type of values being compared
 #
 function verify_ne # <a> <b> <type>
 {
 	typeset a=$1
 	typeset b=$2
 	typeset type=$3
 
 	if [[ $a -eq $b ]]; then
 		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
 }