diff --git a/lib/policy/config/config_test.go b/lib/policy/config/config_test.go
index 40bb6b43..3a96c9c9 100644
--- a/lib/policy/config/config_test.go
+++ b/lib/policy/config/config_test.go
@@ -109,7 +109,7 @@ func TestBotValid(t *testing.T) {
 				Action:    RuleChallenge,
 				PathRegex: p("Mozilla"),
 				Challenge: &ChallengeRules{
-					Difficulty: 0,
+					Difficulty: -1,
 					ReportAs:   4,
 					Algorithm:  "fast",
 				},
diff --git a/lib/policy/config/threshold_test.go b/lib/policy/config/threshold_test.go
index 9024fe80..1c668b2b 100644
--- a/lib/policy/config/threshold_test.go
+++ b/lib/policy/config/threshold_test.go
@@ -70,7 +70,7 @@ func TestThresholdValid(t *testing.T) {
 			name: "challenge invalid",
 			input: &Threshold{
 				Action:    RuleChallenge,
-				Challenge: &ChallengeRules{Difficulty: 0, ReportAs: 0},
+				Challenge: &ChallengeRules{Difficulty: -1, ReportAs: -1},
 			},
 			err: ErrChallengeDifficultyTooLow,
 		},