--- test/testrunner.sh.orig	2021-01-06 15:44:11.000000000 -0800
+++ test/testrunner.sh	2021-01-06 15:50:28.000000000 -0800
@@ -54,18 +54,18 @@
 
 declare -i expectedReturnCode=0
 if [ $(grep -c "^:EXPECTED-ERROR " $testCaseFile) -eq 1 ]; then
-    expectedReturnCode=$(grep "^:EXPECTED-ERROR " $testCaseFile | sed -e 's/:EXPECTED-ERROR //')
+    expectedReturnCode=$(grep "^:EXPECTED-ERROR " $testCaseFile | gsed -e 's/:EXPECTED-ERROR //')
 fi
 
 declare -r testInputFile=${testCaseFile/%.txt/.input.tmp}
 declare -r testExpectationFile=${testCaseFile/%.txt/.expected.tmp}
-declare -r testFilterFile=${testCaseFile/%.txt/.sed.tmp}
+declare -r testFilterFile=${testCaseFile/%.txt/.gsed.tmp}
 declare -r testOutputFile=${testCaseFile/%.txt/.out.tmp}
-declare -r boxesArgs=$(cat $testCaseFile | sed -n '/^:ARGS/,+1p' | grep -v ^:INPUT | sed '1d')
+declare -r boxesArgs=$(cat $testCaseFile | gsed -n '/^:ARGS/,+1p' | grep -v ^:INPUT | gsed '1d')
 
-cat $testCaseFile | sed -n '/^:INPUT/,/^:OUTPUT-FILTER/p;' | sed '1d;$d' | tr -d '\r' > $testInputFile
-cat $testCaseFile | sed -n '/^:OUTPUT-FILTER/,/^:EXPECTED\b.*$/p;' | sed '1d;$d' | tr -d '\r' > $testFilterFile
-cat $testCaseFile | sed -n '/^:EXPECTED/,/^:EOF/p;' | sed '1d;$d' | tr -d '\r' > $testExpectationFile
+cat $testCaseFile | gsed -n '/^:INPUT/,/^:OUTPUT-FILTER/p;' | gsed '1d;$d' | tr -d '\r' > $testInputFile
+cat $testCaseFile | gsed -n '/^:OUTPUT-FILTER/,/^:EXPECTED\b.*$/p;' | gsed '1d;$d' | tr -d '\r' > $testFilterFile
+cat $testCaseFile | gsed -n '/^:EXPECTED/,/^:EOF/p;' | gsed '1d;$d' | tr -d '\r' > $testExpectationFile
 
 declare boxesBinary=../src/boxes.exe
 if [ ! -x $boxesBinary ]; then
@@ -77,7 +77,7 @@
 
 cat $testInputFile | $boxesBinary $boxesArgs >$testOutputFile 2>&1
 declare -ir actualReturnCode=$?
-cat $testOutputFile | tr -d '\r' | sed -f $testFilterFile | diff - $testExpectationFile
+cat $testOutputFile | tr -d '\r' | gsed -f $testFilterFile | diff - $testExpectationFile
 if [ $? -ne 0 ]; then
     >&2 echo "Error in test case: $testCaseFile (top: actual; bottom: expected)"
     exit 5