Test for ability to switch from single to multi-master

pkg/apis/kops/validation/BUILD.bazel

@@ -38,6 +38,7 @@ go_test(
     name = "go_default_test",
     srcs = [
         "aws_test.go",
+        "cluster_test.go",
         "instancegroup_test.go",
         "validation_test.go",
     ],

pkg/apis/kops/validation/cluster_test.go

@@ -0,0 +1,97 @@
+package validation
+
+import (
+	"testing"
+
+	"k8s.io/kops/upup/pkg/fi"
+
+	"k8s.io/kops/pkg/apis/kops"
+)
+
+func TestValidEtcdChanges(t *testing.T) {
+	grid := []struct {
+		OldSpec *kops.EtcdClusterSpec
+		NewSpec *kops.EtcdClusterSpec
+		Status  *kops.ClusterStatus
+		Details string
+	}{
+		{
+			OldSpec: &kops.EtcdClusterSpec{
+				Name: "main",
+				Members: []*kops.EtcdMemberSpec{
+					&kops.EtcdMemberSpec{
+						Name:          "a",
+						InstanceGroup: fi.String("eu-central-1a"),
+					},
+				},
+			},
+
+			NewSpec: &kops.EtcdClusterSpec{
+				Name: "main",
+				Members: []*kops.EtcdMemberSpec{
+					&kops.EtcdMemberSpec{
+						Name:          "a",
+						InstanceGroup: fi.String("eu-central-1a"),
+					},
+					&kops.EtcdMemberSpec{
+						Name:          "b",
+						InstanceGroup: fi.String("eu-central-1b"),
+					},
+					&kops.EtcdMemberSpec{
+						Name:          "c",
+						InstanceGroup: fi.String("eu-central-1c"),
+					},
+				},
+			},
+
+			Status: &kops.ClusterStatus{
+				EtcdClusters: []kops.EtcdClusterStatus{
+					kops.EtcdClusterStatus{
+						Name: "main",
+					},
+				},
+			},
+
+			Details: "Could not update from single to multi-master",
+		},
+
+		{
+			OldSpec: &kops.EtcdClusterSpec{
+				Name: "main",
+				Members: []*kops.EtcdMemberSpec{
+					&kops.EtcdMemberSpec{
+						Name:          "a",
+						InstanceGroup: fi.String("eu-central-1a"),
+					},
+				},
+			},
+
+			NewSpec: &kops.EtcdClusterSpec{
+				Name: "main",
+				Members: []*kops.EtcdMemberSpec{
+					&kops.EtcdMemberSpec{
+						Name:          "a",
+						InstanceGroup: fi.String("eu-central-1a"),
+					},
+				},
+			},
+
+			Status: &kops.ClusterStatus{
+				EtcdClusters: []kops.EtcdClusterStatus{
+					kops.EtcdClusterStatus{
+						Name: "main",
+					},
+				},
+			},
+
+			Details: "Could not update identical specs",
+		},
+	}
+
+	for _, g := range grid {
+		errorList := validateEtcdClusterUpdate(nil, g.NewSpec, g.Status, g.OldSpec)
+		if len(errorList) != 0 {
+			t.Error(g.Details)
+		}
+	}
+}