diff --git a/tests/expression/1.0/Android.bp b/tests/expression/1.0/Android.bp
index 2061283..6acb3f9 100644
--- a/tests/expression/1.0/Android.bp
+++ b/tests/expression/1.0/Android.bp
@@ -2,8 +2,8 @@
 
 genrule {
     name: "android.hardware.tests.expression@1.0_genc++",
-    tool: "hidl-gen",
-    cmd: "$tool -o $genDir -Lc++ -randroid.hardware:hardware/interfaces android.hardware.tests.expression@1.0",
+    tools: ["hidl-gen"],
+    cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces android.hardware.tests.expression@1.0",
     srcs: [
         "IExpression.hal",
         "IExpressionExt.hal",
@@ -16,8 +16,8 @@
 
 genrule {
     name: "android.hardware.tests.expression@1.0_genc++_headers",
-    tool: "hidl-gen",
-    cmd: "$tool -o $genDir -Lc++ -randroid.hardware:hardware/interfaces android.hardware.tests.expression@1.0",
+    tools: ["hidl-gen"],
+    cmd: "$(location hidl-gen) -o $(genDir) -Lc++ -randroid.hardware:hardware/interfaces android.hardware.tests.expression@1.0",
     srcs: [
         "IExpression.hal",
         "IExpressionExt.hal",