diff --git a/android/testing.go b/android/testing.go
index 191cb8d..b36f62c 100644
--- a/android/testing.go
+++ b/android/testing.go
@@ -713,9 +713,11 @@
 
 func (b baseTestingComponent) maybeBuildParamsFromRule(rule string) (TestingBuildParams, []string) {
 	var searchedRules []string
-	for _, p := range b.provider.BuildParamsForTests() {
-		searchedRules = append(searchedRules, p.Rule.String())
-		if strings.Contains(p.Rule.String(), rule) {
+	buildParams := b.provider.BuildParamsForTests()
+	for _, p := range buildParams {
+		ruleAsString := p.Rule.String()
+		searchedRules = append(searchedRules, ruleAsString)
+		if strings.Contains(ruleAsString, rule) {
 			return b.newTestingBuildParams(p), searchedRules
 		}
 	}
@@ -725,7 +727,7 @@
 func (b baseTestingComponent) buildParamsFromRule(rule string) TestingBuildParams {
 	p, searchRules := b.maybeBuildParamsFromRule(rule)
 	if p.Rule == nil {
-		panic(fmt.Errorf("couldn't find rule %q.\nall rules: %v", rule, searchRules))
+		panic(fmt.Errorf("couldn't find rule %q.\nall rules:\n%s", rule, strings.Join(searchRules, "\n")))
 	}
 	return p
 }