fix: Simulation is not deterministic due to GenSignedMockTx (backport c…

…osmos#12374) (cosmos#12403)

CHANGELOG.md

@@ -51,6 +51,7 @@ It is strongly recommended to upgrade to these releases as well.
 
 ### Bug Fixes
 
+* (testutil/sims) [#12374](https://github.com/cosmos/cosmos-sdk/pull/12374) fix the non-determinstic behavior in simulations caused by `GenSignedMockTx` and check empty coins slice before it is used to create `banktype.MsgSend`.
 * [#12448](https://github.com/cosmos/cosmos-sdk/pull/12448) Start telemetry independently from the API server.
 * [#12509](https://github.com/cosmos/cosmos-sdk/pull/12509) Fix `Register{Tx,Tendermint}Service` not being called, resulting in some endpoints like the Simulate endpoint not working.
 

x/genutil/gentx_test.go

@@ -271,9 +271,10 @@ func (suite *GenTxTestSuite) TestDeliverGenTxs() {
 				_ = suite.setAccountBalance(addr1, 50)
 				_ = suite.setAccountBalance(addr2, 1)
 
+				r := rand.New(rand.NewSource(time.Now().UnixNano()))
 				msg := banktypes.NewMsgSend(addr1, addr2, sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 1)})
 				tx, err := helpers.GenSignedMockTx(
-					rand.New(rand.NewSource(time.Now().UnixNano())),
+					r,
 					suite.encodingConfig.TxConfig,
 					[]sdk.Msg{msg},
 					sdk.Coins{sdk.NewInt64Coin(sdk.DefaultBondDenom, 10)},