diff --git a/polkadot/runtime/kusama/src/lib.rs b/polkadot/runtime/kusama/src/lib.rs
index cacac8202b..0780de62c4 100644
--- a/polkadot/runtime/kusama/src/lib.rs
+++ b/polkadot/runtime/kusama/src/lib.rs
@@ -1336,16 +1336,3 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 }
-
-#[cfg(test)]
-mod tests {
-	use super::Runtime;
-
-	#[test]
-	fn slash_defer_less_than_bonding_duration() {
-		assert!(
-			<Runtime as staking::Trait>::SlashDeferDuration::get()
-				< <Runtime as staking::Trait>::BondingDuration::get()
-		);
-	}
-}
diff --git a/polkadot/runtime/polkadot/src/lib.rs b/polkadot/runtime/polkadot/src/lib.rs
index ec3fa30434..13de7985ed 100644
--- a/polkadot/runtime/polkadot/src/lib.rs
+++ b/polkadot/runtime/polkadot/src/lib.rs
@@ -1474,16 +1474,3 @@ sp_api::impl_runtime_apis! {
 		}
 	}
 }
-
-#[cfg(test)]
-mod tests {
-	use super::Runtime;
-
-	#[test]
-	fn slash_defer_less_than_bonding_duration() {
-		assert!(
-			<Runtime as staking::Trait>::SlashDeferDuration::get()
-				< <Runtime as staking::Trait>::BondingDuration::get()
-		);
-	}
-}
diff --git a/polkadot/runtime/test-runtime/src/lib.rs b/polkadot/runtime/test-runtime/src/lib.rs
index d7238b6482..aa92b40e78 100644
--- a/polkadot/runtime/test-runtime/src/lib.rs
+++ b/polkadot/runtime/test-runtime/src/lib.rs
@@ -303,8 +303,8 @@ parameter_types! {
 	pub storage SessionsPerEra: SessionIndex = 6;
 	// 28 eras for unbonding (7 days).
 	pub storage BondingDuration: staking::EraIndex = 28;
-	// 28 eras in which slashes can be cancelled (7 days).
-	pub storage SlashDeferDuration: staking::EraIndex = 28;
+	// 27 eras in which slashes can be cancelled (a bit less than 7 days).
+	pub storage SlashDeferDuration: staking::EraIndex = 27;
 	pub const RewardCurve: &'static PiecewiseLinear<'static> = &REWARD_CURVE;
 	pub storage MaxNominatorRewardedPerValidator: u32 = 64;
 	pub storage ElectionLookahead: BlockNumber = 0;
diff --git a/polkadot/runtime/westend/src/lib.rs b/polkadot/runtime/westend/src/lib.rs
index c5d3669d0f..7e2cb3a71d 100644
--- a/polkadot/runtime/westend/src/lib.rs
+++ b/polkadot/runtime/westend/src/lib.rs
@@ -1113,15 +1113,3 @@ sp_api::impl_runtime_apis! {
 	}
 }
 
-#[cfg(test)]
-mod tests {
-	use super::Runtime;
-
-	#[test]
-	fn slash_defer_less_than_bonding_duration() {
-		assert!(
-			<Runtime as staking::Trait>::SlashDeferDuration::get()
-				< <Runtime as staking::Trait>::BondingDuration::get()
-		);
-	}
-}