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: mismatched_locality.go
    path of file: ./repos/cockroach/pkg/cmd/roachtest/tests
    
    the code of the file until where you have to start completion: // Copyright 2023 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.

package tests

import (
	"context"

	"github.com/cockroachdb/cockroach/pkg/cmd/roachtest/cluster"
	"github.com/cockroachdb/cockroach/pkg/cmd/roachtest/option"
	"github.com/cockroachdb/cockroach/pkg/cmd/roachtest/test"
	"github.com/cockroachdb/cockroach/pkg/roachprod/install"
)

// This test tests that we can add and drop regions even if the locality flags
// of a node no longer match the regions that already were added to the
// database.
func runMismatchedLocalityTest(ctx context.Context, t test.Test, c cluster.Cluster) {
	// Start 3 nodes with a different localities.
	startOpts := option.DefaultStartOpts()
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=east"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(1))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=central"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(2))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=west"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(3))

	// Add the 3 regions to the database.
	db := c.Conn(ctx, t.L(), 1)
	if _, err := db.Exec(`ALTER DATABASE defaultdb PRIMARY REGION "east";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "central";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "west";`); err != nil {
		t.Fatal(err)
	}

	// Restart all the nodes with new localities.
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), c.Nodes(1))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=mars"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(1))
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), c.Nodes(2))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=jupiter"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(2))
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), 
    
func runMismatchedLocalityTest(ctx context.Context, t test.Test, c cluster.Cluster) {
	// Start 3 nodes with a different localities.
	startOpts := option.DefaultStartOpts()
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=east"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(1))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=central"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(2))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=west"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(3))

	// Add the 3 regions to the database.
	db := c.Conn(ctx, t.L(), 1)
	if _, err := db.Exec(`ALTER DATABASE defaultdb PRIMARY REGION "east";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "central";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "west";`); err != nil {
		t.Fatal(err)
	}

	// Restart all the nodes with new localities.
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), c.Nodes(1))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=mars"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(1))
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), c.Nodes(2))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=jupiter"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(2))
	c.Stop(ctx, t.L(), option.DefaultStopOpts(), c.Nodes(3))
	startOpts.RoachprodOpts.ExtraArgs = []string{"--locality=region=venus"}
	c.Start(ctx, t.L(), startOpts, install.MakeClusterSettings(), c.Nodes(3))

	// Verify that we can add and drop regions for the database. There's no longer
	// any node with the old localities, but that's fine.
	db = c.Conn(ctx, t.L(), 3)
	if err := WaitFor3XReplication(ctx, t, t.L(), db); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "venus";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb DROP REGION "central";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "jupiter";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb ADD REGION "mars";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb SET PRIMARY REGION "mars";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb DROP REGION "west";`); err != nil {
		t.Fatal(err)
	}
	if _, err := db.Exec(`ALTER DATABASE defaultdb DROP REGION "east";`); err != nil {
		t.Fatal(err)
	}
}