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: system_test.go
    path of file: ./repos/rancher/pkg/catalogv2/system
    
    the code of the file until where you have to start completion: package system

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"testing"
	"time"

	types2 "github.com/rancher/rancher/pkg/api/steve/catalog/types"
	catalog "github.com/rancher/rancher/pkg/apis/catalog.cattle.io/v1"
	"github.com/rancher/rancher/pkg/catalogv2/system/mocks"
	"github.com/stretchr/testify/mock"
	"helm.sh/helm/v3/pkg/action"
	"helm.sh/helm/v3/pkg/repo"
	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"

	"github.com/stretchr/testify/as
    
func TestGetIntervalOrDefault(t *testing.T) {
	t.Parallel()
	asserts := assert.New(t)
	type testCase struct {
		name     string
		input    string
		expected time.Duration
	}

	testCases := []testCase{
		{
			name:     "Should return the default value of 21600 if input string is empty",
			input:    "",
			expected: 21600 * time.Second,
		},
		{
			name:     "Should return the default value of 21600 if input string is invalid",
			input:    "foo",
			expected: 21600 * time.Second,
		},
		{
			name:     "Should return the time.Duration that corresponds to the given input",
			input:    "60",
			expected: 60 * time.Second,
		},
	}

	for _, test := range testCases {
		actual := getIntervalOrDefault(test.input)
		asserts.Equal(test.expected, actual, test.name)
	}
}