diff --git a/rhp/v4/rpc_test.go b/rhp/v4/rpc_test.go
index 266b06c..38a52d5 100644
--- a/rhp/v4/rpc_test.go
+++ b/rhp/v4/rpc_test.go
@@ -752,6 +752,19 @@ func TestAccounts(t *testing.T) {
 
 	cs := cm.TipState()
 
+	// test operations against unknown account
+	token := proto4.AccountToken{
+		Account:    account,
+		ValidUntil: time.Now().Add(time.Hour),
+	}
+
+	tokenSigHash := token.SigHash()
+	token.Signature = renterKey.SignHash(tokenSigHash)
+	_, err = rhp4.RPCVerifySector(context.Background(), transport, settings.Prices, token, types.Hash256{1})
+	if err == nil || !strings.Contains(err.Error(), proto4.ErrNotEnoughFunds.Error()) {
+		t.Fatal(err)
+	}
+
 	balance, err := rhp4.RPCAccountBalance(context.Background(), transport, account)
 	if err != nil {
 		t.Fatal(err)
@@ -803,6 +816,13 @@ func TestAccounts(t *testing.T) {
 	} else if !balance.Equals(accountFundAmount) {
 		t.Fatalf("expected %v, got %v", accountFundAmount, balance)
 	}
+
+	// drain account and try using it
+	_ = c.DebitAccount(account, proto4.Usage{RPC: accountFundAmount})
+	_, err = rhp4.RPCVerifySector(context.Background(), transport, settings.Prices, token, types.Hash256{1})
+	if err == nil || !strings.Contains(err.Error(), proto4.ErrNotEnoughFunds.Error()) {
+		t.Fatal(err)
+	}
 }
 
 func TestReadWriteSector(t *testing.T) {
diff --git a/testutil/host.go b/testutil/host.go
index 5fb8bc5..f22b617 100644
--- a/testutil/host.go
+++ b/testutil/host.go
@@ -252,10 +252,8 @@ func (ec *EphemeralContractor) DebitAccount(account proto4.Account, usage proto4
 	defer ec.mu.Unlock()
 
 	balance, ok := ec.accounts[account]
-	if !ok {
-		return errors.New("account not found")
-	} else if balance.Cmp(usage.RenterCost()) < 0 {
-		return errors.New("insufficient funds")
+	if !ok || balance.Cmp(usage.RenterCost()) < 0 {
+		return proto4.ErrNotEnoughFunds
 	}
 	ec.accounts[account] = balance.Sub(usage.RenterCost())
 	return nil