You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: modelcredential_test.go
    path of file: ./repos/juju/state
    
    the code of the file until where you have to start completion: // Copyright 2018 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package state_test

import (
	"fmt"

	"github.com/juju/names/v5"
	jc "github.com/juju/testing/checkers"
	"github.com/juju/utils/v3"
	gc "gopkg.in/check.v1"

	"github.com/juju/juju/cloud"
	"github.com/juju/juju/core/status"
	"github.com/juju/juju/state"
	statetesting "github.com/juju/juju/state/testing"
	"github.com/juju/juju/storage"
	"github.com/juju/juju/testing"
	"github.com/juju/juju/testing/factory"
)

type ModelCredentialSuite struct {
	ConnSuite

	credentialTag names.CloudCredentialTag
}

var _ = gc.Suite(&ModelCredentialSuite{})

func (s *ModelCredentialSuite) SetUpTest(c *gc.C) {
	s.ConnSuite.SetUpTest(c)

	s.credentialTag = s.createCloudCredential(c, "foobar")
}

func (s *ModelCredentialSuite) TestInvalidateModelCreden
    
func (s *ModelCredentialSuite) TestInvalidateModelCredentialTouchesAllCredentialModels(c *gc.C) {
	// This test checks that all models are affected when one of them invalidates a credential they all use...

	// 1. create a credential
	cloudName, credentialOwner, credentialTag := assertCredentialCreated(c, s.ConnSuite)

	// 2. create some models to use it
	modelUUIDs := make([]string, 5)
	for i := 0; i < 5; i++ {
		modelUUIDs[i] = assertModelCreated(c, s.ConnSuite, cloudName, credentialTag, credentialOwner.Tag(), fmt.Sprintf("model-for-cloud%v", i))
	}

	// 3. invalidate credential
	oneModelState, helper, err := s.StatePool.GetModel(modelUUIDs[0])
	c.Assert(err, jc.ErrorIsNil)
	defer helper.Release()
	c.Assert(oneModelState.State().InvalidateModelCredential("testing invalidate for all credential models"), jc.ErrorIsNil)

	// 4. check all models are suspended
	for _, uuid := range modelUUIDs {
		assertModelStatus(c, s.StatePool, uuid, status.Suspended)
		assertModelHistories(c, s.StatePool, uuid, status.Suspended, status.Available)
	}
}