rbd: add validation to ToCSI() for rbdVolume and rbdSnapshot

After an unfortnate timed restart of the provisioner, a volume that got
cloned did not get a `rbdVolume.VolID` set. The `.VolID` is used as the
CSI Volume Handle, and is a required attribute.

The `rbdVolume` and `rbdSnapshot` structs have a `.ToCSI()` function
that can do the validation of required attributes. This is now added,
including unit-tests.

Signed-off-by: Niels de Vos <ndevos@ibm.com>

internal/rbd/controllerserver_test.go

@@ -16,7 +16,10 @@ limitations under the License.
 
 package rbd
 
-import "testing"
+import (
+	"context"
+	"testing"
+)
 
 func TestValidateStriping(t *testing.T) {
 	t.Parallel()
@@ -85,3 +88,81 @@ func TestValidateStriping(t *testing.T) {
 		})
 	}
 }
+
+func TestToCSIVolume(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name    string
+		rv      *rbdVolume
+		wantErr bool
+	}{
+		{
+			name: "all attributes set",
+			rv: &rbdVolume{
+				rbdImage: rbdImage{
+					VolID:        "0001-unique-volume-id",
+					Pool:         "ecpool",
+					JournalPool:  "replicapool",
+					RbdImageName: "csi-vol-01234-5678-90abc",
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "missing volume-id",
+			rv: &rbdVolume{
+				rbdImage: rbdImage{
+					VolID:        "",
+					Pool:         "ecpool",
+					JournalPool:  "replicapool",
+					RbdImageName: "csi-vol-01234-5678-90abc",
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing pool",
+			rv: &rbdVolume{
+				rbdImage: rbdImage{
+					VolID:        "0001-unique-volume-id",
+					Pool:         "",
+					JournalPool:  "replicapool",
+					RbdImageName: "csi-vol-01234-5678-90abc",
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing journal-pool",
+			rv: &rbdVolume{
+				rbdImage: rbdImage{
+					VolID:        "0001-unique-volume-id",
+					Pool:         "ecpool",
+					JournalPool:  "",
+					RbdImageName: "csi-vol-01234-5678-90abc",
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing image-name",
+			rv: &rbdVolume{
+				rbdImage: rbdImage{
+					VolID:        "0001-unique-volume-id",
+					Pool:         "ecpool",
+					JournalPool:  "",
+					RbdImageName: "",
+				},
+			},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			if _, err := tt.rv.ToCSI(context.TODO()); (err != nil) != tt.wantErr {
+				t.Errorf("ToCSI() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}