diff --git a/libwvdrmengine/run_all_unit_tests.sh b/libwvdrmengine/run_all_unit_tests.sh
index 1ebe4265..d993fd2b 100755
--- a/libwvdrmengine/run_all_unit_tests.sh
+++ b/libwvdrmengine/run_all_unit_tests.sh
@@ -3,11 +3,15 @@
 final_result=0
 failed_tests=()
 
+if [ -z "$GTEST_FILTER" ]; then
+  GTEST_FILTER="*"
+fi
+
 # Execute a command in "adb shell" and capture the result.
 adb_shell_run() {
   local tmp_log="$OUT/mediadrmtest.log"
   local adb_error="[ADB SHELL] $@ failed"
-  adb shell GTEST_FILTER=$GTEST_FILTER $@ \|\| echo "$adb_error" | tee "$tmp_log"
+  adb shell "GTEST_FILTER=$GTEST_FILTER $@" \|\| echo "$adb_error" | tee "$tmp_log"
   ! grep -Fq "$adb_error" "$tmp_log"
   local result=$?
   if [ $result -ne 0 ]; then