refactor: staking module using mocks (cosmos#12827)

## Description

Closes: cosmos#12504 


---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/main/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/main/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

scripts/mockgen.sh

@@ -24,3 +24,4 @@ $mockgen_cmd -source=x/evidence/types/expected_keepers.go -package testutil -des
 $mockgen_cmd -source=x/slashing/types/expected_keepers.go -package testutil -destination x/slashing/testutil/expected_keepers_mocks.go
 $mockgen_cmd -source=x/genutil/types/expected_keepers.go -package testutil -destination x/genutil/testutil/expected_keepers_mocks.go
 $mockgen_cmd -source=x/gov/testutil/expected_keepers.go -package testutil -destination x/gov/testutil/expected_keepers_mocks.go
+$mockgen_cmd -source=x/staking/types/expected_keepers.go -package testutil -destination x/staking/testutil/expected_keepers_mocks.go

tests/e2e/staking/client/testutil/cli_test.go

@@ -8,13 +8,11 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/simapp"
 	"github.com/cosmos/cosmos-sdk/testutil/network"
-	"github.com/cosmos/cosmos-sdk/x/staking/client/testutil"
-
 	"github.com/stretchr/testify/suite"
 )
 
 func TestIntegrationTestSuite(t *testing.T) {
 	cfg := network.DefaultConfig(simapp.NewTestNetworkFixture)
 	cfg.NumValidators = 2
-	suite.Run(t, testutil.NewIntegrationTestSuite(cfg))
+	suite.Run(t, NewIntegrationTestSuite(cfg))
 }

tests/integration/staking/keeper/delegation_test.go

@@ -0,0 +1,98 @@
+package keeper_test
+
+import (
+	"testing"
+	"time"
+
+	"cosmossdk.io/math"
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/simapp"
+	simtestutil "github.com/cosmos/cosmos-sdk/testutil/sims"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	"github.com/cosmos/cosmos-sdk/x/bank/testutil"
+	"github.com/cosmos/cosmos-sdk/x/staking/keeper"
+	"github.com/cosmos/cosmos-sdk/x/staking/teststaking"
+	"github.com/cosmos/cosmos-sdk/x/staking/types"
+)
+
+func TestUnbondingDelegationsMaxEntries(t *testing.T) {
+	_, app, ctx := createTestInput(t)
+
+	addrDels := simapp.AddTestAddrsIncremental(app, ctx, 1, sdk.NewInt(10000))
+	addrVals := simtestutil.ConvertAddrsToValAddrs(addrDels)
+
+	startTokens := app.StakingKeeper.TokensFromConsensusPower(ctx, 10)
+
+	bondDenom := app.StakingKeeper.BondDenom(ctx)
+	notBondedPool := app.StakingKeeper.GetNotBondedPool(ctx)
+
+	require.NoError(t, testutil.FundModuleAccount(app.BankKeeper, ctx, notBondedPool.GetName(), sdk.NewCoins(sdk.NewCoin(bondDenom, startTokens))))
+	app.AccountKeeper.SetModuleAccount(ctx, notBondedPool)
+
+	// create a validator and a delegator to that validator
+	validator := teststaking.NewValidator(t, addrVals[0], PKs[0])
+
+	validator, issuedShares := validator.AddTokensFromDel(startTokens)
+	require.Equal(t, startTokens, issuedShares.RoundInt())
+
+	validator = keeper.TestingUpdateValidator(app.StakingKeeper, ctx, validator, true)
+	require.True(math.IntEq(t, startTokens, validator.BondedTokens()))
+	require.True(t, validator.IsBonded())
+
+	delegation := types.NewDelegation(addrDels[0], addrVals[0], issuedShares)
+	app.StakingKeeper.SetDelegation(ctx, delegation)
+
+	maxEntries := app.StakingKeeper.MaxEntries(ctx)
+
+	oldBonded := app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	oldNotBonded := app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+
+	// should all pass
+	var completionTime time.Time
+	for i := int64(0); i < int64(maxEntries); i++ {
+		var err error
+		ctx = ctx.WithBlockHeight(i)
+		completionTime, err = app.StakingKeeper.Undelegate(ctx, addrDels[0], addrVals[0], math.LegacyNewDec(1))
+		require.NoError(t, err)
+	}
+
+	newBonded := app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	newNotBonded := app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+	require.True(math.IntEq(t, newBonded, oldBonded.SubRaw(int64(maxEntries))))
+	require.True(math.IntEq(t, newNotBonded, oldNotBonded.AddRaw(int64(maxEntries))))
+
+	oldBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	oldNotBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+
+	// an additional unbond should fail due to max entries
+	_, err := app.StakingKeeper.Undelegate(ctx, addrDels[0], addrVals[0], math.LegacyNewDec(1))
+	require.Error(t, err)
+
+	newBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	newNotBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+
+	require.True(math.IntEq(t, newBonded, oldBonded))
+	require.True(math.IntEq(t, newNotBonded, oldNotBonded))
+
+	// mature unbonding delegations
+	ctx = ctx.WithBlockTime(completionTime)
+	_, err = app.StakingKeeper.CompleteUnbonding(ctx, addrDels[0], addrVals[0])
+	require.NoError(t, err)
+
+	newBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	newNotBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+	require.True(math.IntEq(t, newBonded, oldBonded))
+	require.True(math.IntEq(t, newNotBonded, oldNotBonded.SubRaw(int64(maxEntries))))
+
+	oldNotBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+
+	// unbonding  should work again
+	_, err = app.StakingKeeper.Undelegate(ctx, addrDels[0], addrVals[0], math.LegacyNewDec(1))
+	require.NoError(t, err)
+
+	newBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetBondedPool(ctx).GetAddress(), bondDenom).Amount
+	newNotBonded = app.BankKeeper.GetBalance(ctx, app.StakingKeeper.GetNotBondedPool(ctx).GetAddress(), bondDenom).Amount
+	require.True(math.IntEq(t, newBonded, oldBonded.SubRaw(1)))
+	require.True(math.IntEq(t, newNotBonded, oldNotBonded.AddRaw(1)))
+}