fixed test on CentOS7
diff --git a/tests/playTests.sh b/tests/playTests.sh
index a1893cd..2f9bf04 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -196,10 +196,14 @@
cp *.c dirTestDict
cp ../programs/*.c dirTestDict
cp ../programs/*.h dirTestDict
-cat dirTestDict/* | $MD5SUM > tmph1 # note : we expect same file order to generate same hash
-$ZSTD -f dirTestDict/* -D tmpDictC
-$ZSTD -d dirTestDict/*.zst -D tmpDictC -c | $MD5SUM > tmph2
-diff -q tmph1 tmph2
+$MD5SUM dirTestDict/* > tmph1
+$ZSTD -f --rm dirTestDict/* -D tmpDictC
+$ZSTD -d --rm dirTestDict/*.zst -D tmpDictC # note : use internal checksum
+if [[ "$OSTYPE" == "darwin"* ]]; then
+ $ECHO "test skipped on OS-X" # not compatible with OS-X's md5
+else
+ $MD5SUM -c tmph1
+fi
rm -rf dirTestDict
rm tmp*