diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index fbea557..d977994 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -120,6 +120,9 @@
 # Treat uninitialised variables as errors.
 set -e -o pipefail -u
 
+# Enable ksh/bash extended file matching patterns
+shopt -s extglob
+
 pre_check_environment () {
     if [ -d library -a -d include -a -d tests ]; then :; else
         echo "Must be run from mbed TLS root" >&2
@@ -295,7 +298,7 @@
               -iname CMakeCache.txt -o \
               -path './cmake/*.cmake' \) -exec rm -f {} \+
     # Recover files overwritten by in-tree CMake builds
-    rm -f include/Makefile include/mbedtls/Makefile programs/*/Makefile
+    rm -f include/Makefile include/mbedtls/Makefile programs/!(fuzz)/Makefile
 
     # Remove any artifacts from the component_test_cmake_as_subdirectory test.
     rm -rf programs/test/cmake_subproject/build