diff --git a/tests/char-class-multibyte b/tests/char-class-multibyte
index fae7511..459d10c 100755
--- a/tests/char-class-multibyte
+++ b/tests/char-class-multibyte
@@ -24,7 +24,7 @@ done
 
 for LOC in en_US.UTF-8 $LOCALE_FR_UTF8; do
   out=out3-$LOC
-  printf '\xc3\n' | LC_ALL=$LOC grep '[é]' > $out
+  printf '\303\n' | LC_ALL=$LOC grep '[é]' > $out
   test $? = 1 || fail=1
 done
 
diff --git a/tests/pcre-utf8 b/tests/pcre-utf8
index 7fc6a80..396a3bd 100755
--- a/tests/pcre-utf8
+++ b/tests/pcre-utf8
@@ -16,7 +16,7 @@ fail=0
 echo '$' | LC_ALL=en_US.UTF-8 grep -qP '\p{S}' \
   || skip_ 'PCRE support is compiled out, or it does not support properties'
 
-euro='\xe2\x82\xac euro'
+euro='\342\202\254 euro'
 printf "$euro\\n" > in || framework_failure_
 
 LC_ALL=en_US.UTF-8 grep -P '^\p{S}' in > out || fail=1
diff --git a/tests/turkish-I b/tests/turkish-I
index 35a3753..903fb36 100755
--- a/tests/turkish-I
+++ b/tests/turkish-I
@@ -23,7 +23,7 @@ require_compiled_in_MB_support
 
 fail=0
 
-i='\xC4\xB0'
+i='\304\260'
 printf "$i$i$i$i$i$i$i\n" > in || framework_failure_
 
 LC_ALL=en_US.UTF-8 grep -i .... in > out || fail=1
diff --git a/tests/turkish-I-without-dot b/tests/turkish-I-without-dot
index 9f92502..530c3b6 100755
--- a/tests/turkish-I-without-dot
+++ b/tests/turkish-I-without-dot
@@ -47,7 +47,7 @@ compare out in || fail=1
 # buffer have precisely the same length (22 bytes here), yet internal
 # offsets do differ.  Lengths are the same because while some bytes shrink
 # when converted to lower case, others grow, and here they balance out.
-i='I\xC4\xB0'
+i='I\304\260'
 printf "$i$i$i$i$i$i$i\n" > in || framework_failure_
 LC_ALL=tr_TR.utf8 grep -i .... in > out || fail=1
 compare out in || fail=1
diff --git a/tests/unibyte-bracket-expr b/tests/unibyte-bracket-expr
index 08b1b5b..4dbb8bb 100755
--- a/tests/unibyte-bracket-expr
+++ b/tests/unibyte-bracket-expr
@@ -27,13 +27,15 @@ export LC_ALL
 
 fail=0
 
-for i in 8 9 a b c d e f; do
-  for j in 0 1 2 3 4 5 6 7 8 9 a b c d e f; do
-    in=in-$i$j
-    b=$(printf "\\x$i$j")
-    echo "$b" > $in || framework_failure_
-    grep "[$b]" $in > out || fail=1
-    compare out $in || fail=1
+for i in 2 3; do
+  for j in 0 1 2 3 4 5 6 7; do
+    for k in 0 1 2 3 4 5 6 7; do
+      in=in-$i$j$k
+      b=$(printf "\\$i$j$k")
+      echo "$b" > $in || framework_failure_
+      grep "[$b]" $in > out || fail=1
+      compare out $in || fail=1
+    done
   done
 done
 
