diff --git a/x/foundation/keeper/internal/treasury_test.go b/x/foundation/keeper/internal/treasury_test.go
index 3609fe3c5c..717173d94e 100644
--- a/x/foundation/keeper/internal/treasury_test.go
+++ b/x/foundation/keeper/internal/treasury_test.go
@@ -7,29 +7,52 @@ import (
 )
 
 func (s *KeeperTestSuite) TestCollectFoundationTax() {
+	ctx, _ := s.ctx.CacheContext()
+
+	// empty fee collector first
+	// send the fee to the stranger
+	// and get it back later if the test case requires
+	collector := authtypes.NewModuleAddress(authtypes.FeeCollectorName)
+	fees := s.bankKeeper.GetAllBalances(ctx, collector)
+	s.bankKeeper.SendCoinsFromModuleToAccount(ctx, authtypes.FeeCollectorName, s.stranger, fees)
+
 	for name, tc := range map[string]struct {
+		fee      sdk.Int
 		taxRatio sdk.Dec
 		tax      sdk.Int
 		valid    bool
 	}{
 		"common": {
+			fee:      fees[0].Amount,
 			taxRatio: sdk.MustNewDecFromStr("0.123456789"),
 			tax:      sdk.NewInt(121932631),
 			valid:    true,
 		},
+		"zero fee": {
+			fee:      sdk.ZeroInt(),
+			taxRatio: sdk.MustNewDecFromStr("0.123456789"),
+			tax:      sdk.ZeroInt(),
+			valid:    true,
+		},
 		"zero ratio": {
+			fee:      fees[0].Amount,
 			taxRatio: sdk.ZeroDec(),
 			tax:      sdk.ZeroInt(),
 			valid:    true,
 		},
 		"send fails": {
+			fee:      fees[0].Amount,
 			taxRatio: sdk.MustNewDecFromStr("1.00000001"),
 			tax:      sdk.NewInt(987654330),
 		},
 	} {
 		s.Run(name, func() {
-			ctx, _ := s.ctx.CacheContext()
+			ctx, _ := ctx.CacheContext()
+
+			// set fee
+			s.bankKeeper.SendCoinsFromAccountToModule(ctx, s.stranger, authtypes.FeeCollectorName, sdk.NewCoins(sdk.NewCoin(fees[0].Denom, tc.fee)))
 
+			// set tax ratio
 			s.impl.SetParams(ctx, foundation.Params{
 				FoundationTax: tc.taxRatio,
 			})
@@ -38,7 +61,7 @@ func (s *KeeperTestSuite) TestCollectFoundationTax() {
 			s.Require().Equal(1, len(before))
 			s.Require().Equal(sdk.NewDecFromInt(s.balance), before[0].Amount)
 
-			tax := sdk.NewDecFromInt(s.balance).MulTruncate(tc.taxRatio).TruncateInt()
+			tax := sdk.NewDecFromInt(tc.fee).MulTruncate(tc.taxRatio).TruncateInt()
 			// ensure the behavior does not change
 			s.Require().Equal(tc.tax, tax)