Adding extra test case to cover the basePath = '/' case

This has come up in several issues on the repo where people set
basePath to `/` and this leads to problems. This proves this PR
resolves that issue and doesn't lead to the problems of a path like
`//`

pkg/driver/controller_test.go

@@ -4,14 +4,16 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"regexp"
+	"testing"
+
 	"github.com/google/uuid"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	"regexp"
-	"testing"
 
 	"github.com/container-storage-interface/spec/lib/go/csi"
 	"github.com/golang/mock/gomock"
+
 	"github.com/kubernetes-sigs/aws-efs-csi-driver/pkg/cloud"
 	"github.com/kubernetes-sigs/aws-efs-csi-driver/pkg/driver/mocks"
 )
@@ -829,6 +831,75 @@ func TestCreateVolume(t *testing.T) {
 				mockCtl.Finish()
 			},
 		},
+		{
+			name: "Success: Normal flow with an empty subPath Pattern, and basePath set to /",
+			testFunc: func(t *testing.T) {
+				mockCtl := gomock.NewController(t)
+				mockCloud := mocks.NewMockCloud(mockCtl)
+
+				driver := &Driver{
+					endpoint:     endpoint,
+					cloud:        mockCloud,
+					gidAllocator: NewGidAllocator(),
+					tags:         parseTagsFromStr(""),
+				}
+
+				req := &csi.CreateVolumeRequest{
+					Name: volumeName,
+					VolumeCapabilities: []*csi.VolumeCapability{
+						stdVolCap,
+					},
+					CapacityRange: &csi.CapacityRange{
+						RequiredBytes: capacityRange,
+					},
+					Parameters: map[string]string{
+						ProvisioningMode:      "efs-ap",
+						FsId:                  fsId,
+						GidMin:                "1000",
+						GidMax:                "2000",
+						DirectoryPerms:        "777",
+						SubPathPattern:        "",
+						BasePath:              "/",
+						EnsureUniqueDirectory: "false",
+					},
+				}
+
+				ctx := context.Background()
+				fileSystem := &cloud.FileSystem{
+					FileSystemId: fsId,
+				}
+				accessPoint := &cloud.AccessPoint{
+					AccessPointId: apId,
+					FileSystemId:  fsId,
+				}
+				mockCloud.EXPECT().DescribeFileSystem(gomock.Eq(ctx), gomock.Any()).Return(fileSystem, nil)
+
+				mockCloud.EXPECT().CreateAccessPoint(gomock.Eq(ctx), gomock.Any(), gomock.Any()).Return(accessPoint, nil).
+					Do(func(ctx context.Context, volumeName string, accessPointOpts *cloud.AccessPointOptions) {
+						if accessPointOpts.DirectoryPath != "/" {
+							t.Fatalf("Root directory mismatch. Expected: %v, actual: %v",
+								"/",
+								accessPointOpts.DirectoryPath)
+						}
+					})
+
+				res, err := driver.CreateVolume(ctx, req)
+
+				if err != nil {
+					t.Fatalf("CreateVolume failed: %v", err)
+				}
+
+				if res.Volume == nil {
+					t.Fatal("Volume is nil")
+				}
+
+				if res.Volume.VolumeId != volumeId {
+					t.Fatalf("Volume Id mismatched. Expected: %v, Actual: %v", volumeId, res.Volume.VolumeId)
+				}
+
+				mockCtl.Finish()
+			},
+		},
 		{
 			name: "Fail: Volume name missing",
 			testFunc: func(t *testing.T) {