kubernetes: add tests for endpoint/service-import equivalence checks (#8368)

Signed-off-by: yashsingh74 <yashsingh1774@gmail.com>

plugin/kubernetes/controller_equivalence_test.go

@@ -0,0 +1,155 @@
+package kubernetes
+
+import (
+	"testing"
+
+	"github.com/coredns/coredns/plugin/kubernetes/object"
+
+	mcs "sigs.k8s.io/mcs-api/pkg/apis/v1alpha1"
+)
+
+// TestSubsetsEquivalent checks that subsetsEquivalent only treats two subsets
+// as equal when their addresses and ports match exactly.
+func TestSubsetsEquivalent(t *testing.T) {
+	base := object.EndpointSubset{
+		Addresses: []object.EndpointAddress{{IP: "10.0.0.1", Hostname: "a"}},
+		Ports:     []object.EndpointPort{{Name: "http", Port: 80, Protocol: "TCP"}},
+	}
+
+	tests := []struct {
+		name string
+		a    object.EndpointSubset
+		b    object.EndpointSubset
+		want bool
+	}{
+		{"identical", base, base, true},
+		{"different address count", base, object.EndpointSubset{
+			Addresses: []object.EndpointAddress{},
+			Ports:     base.Ports,
+		}, false},
+		{"different port count", base, object.EndpointSubset{
+			Addresses: base.Addresses,
+			Ports:     []object.EndpointPort{},
+		}, false},
+		{"different ip", base, object.EndpointSubset{
+			Addresses: []object.EndpointAddress{{IP: "10.0.0.2", Hostname: "a"}},
+			Ports:     base.Ports,
+		}, false},
+		{"different hostname", base, object.EndpointSubset{
+			Addresses: []object.EndpointAddress{{IP: "10.0.0.1", Hostname: "b"}},
+			Ports:     base.Ports,
+		}, false},
+		{"different port number", base, object.EndpointSubset{
+			Addresses: base.Addresses,
+			Ports:     []object.EndpointPort{{Name: "http", Port: 8080, Protocol: "TCP"}},
+		}, false},
+		{"different port protocol", base, object.EndpointSubset{
+			Addresses: base.Addresses,
+			Ports:     []object.EndpointPort{{Name: "http", Port: 80, Protocol: "UDP"}},
+		}, false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := subsetsEquivalent(tc.a, tc.b); got != tc.want {
+				t.Errorf("subsetsEquivalent() = %v, want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+// TestEndpointsEquivalent checks endpointsEquivalent's nil handling and its
+// comparison of subsets across two Endpoints objects.
+func TestEndpointsEquivalent(t *testing.T) {
+	subset := object.EndpointSubset{
+		Addresses: []object.EndpointAddress{{IP: "10.0.0.1"}},
+		Ports:     []object.EndpointPort{{Name: "http", Port: 80, Protocol: "TCP"}},
+	}
+	a := &object.Endpoints{Subsets: []object.EndpointSubset{subset}}
+	b := &object.Endpoints{Subsets: []object.EndpointSubset{subset}}
+
+	if !endpointsEquivalent(a, b) {
+		t.Error("expected equivalent endpoints to be equivalent")
+	}
+
+	if endpointsEquivalent(nil, b) {
+		t.Error("expected nil endpoints to not be equivalent")
+	}
+	if endpointsEquivalent(a, nil) {
+		t.Error("expected nil endpoints to not be equivalent")
+	}
+
+	c := &object.Endpoints{Subsets: []object.EndpointSubset{subset, subset}}
+	if endpointsEquivalent(a, c) {
+		t.Error("expected endpoints with different subset counts to not be equivalent")
+	}
+
+	d := &object.Endpoints{Subsets: []object.EndpointSubset{{
+		Addresses: []object.EndpointAddress{{IP: "10.0.0.2"}},
+		Ports:     subset.Ports,
+	}}}
+	if endpointsEquivalent(a, d) {
+		t.Error("expected endpoints with different addresses to not be equivalent")
+	}
+}
+
+// TestMulticlusterEndpointsEquivalent checks that multiclusterEndpointsEquivalent
+// also accounts for ClusterId on top of the embedded Endpoints comparison.
+func TestMulticlusterEndpointsEquivalent(t *testing.T) {
+	ep := object.Endpoints{Subsets: []object.EndpointSubset{{
+		Addresses: []object.EndpointAddress{{IP: "10.0.0.1"}},
+		Ports:     []object.EndpointPort{{Name: "http", Port: 80, Protocol: "TCP"}},
+	}}}
+
+	a := &object.MultiClusterEndpoints{Endpoints: ep, ClusterId: "cluster1"}
+	b := &object.MultiClusterEndpoints{Endpoints: ep, ClusterId: "cluster1"}
+	if !multiclusterEndpointsEquivalent(a, b) {
+		t.Error("expected equivalent multicluster endpoints to be equivalent")
+	}
+
+	c := &object.MultiClusterEndpoints{Endpoints: ep, ClusterId: "cluster2"}
+	if multiclusterEndpointsEquivalent(a, c) {
+		t.Error("expected different cluster ids to not be equivalent")
+	}
+
+	if multiclusterEndpointsEquivalent(nil, b) {
+		t.Error("expected nil multicluster endpoints to not be equivalent")
+	}
+}
+
+// TestServiceImportEquivalent checks serviceImportEquivalent's add/remove
+// handling and its comparison of type and ports.
+func TestServiceImportEquivalent(t *testing.T) {
+	svc := &object.ServiceImport{
+		Type:  mcs.ClusterSetIP,
+		Ports: []mcs.ServicePort{{Name: "http", Port: 80, Protocol: "TCP"}},
+	}
+	svcCopy := &object.ServiceImport{
+		Type:  svc.Type,
+		Ports: svc.Ports,
+	}
+
+	if !serviceImportEquivalent(svc, svcCopy) {
+		t.Error("expected equivalent service imports to be equivalent")
+	}
+
+	if serviceImportEquivalent(svc, nil) {
+		t.Error("expected added/removed service import to not be equivalent")
+	}
+	if serviceImportEquivalent(nil, svc) {
+		t.Error("expected added/removed service import to not be equivalent")
+	}
+
+	diffType := &object.ServiceImport{Type: mcs.Headless, Ports: svc.Ports}
+	if serviceImportEquivalent(svc, diffType) {
+		t.Error("expected different types to not be equivalent")
+	}
+
+	diffPorts := &object.ServiceImport{
+		Type:  svc.Type,
+		Ports: []mcs.ServicePort{{Name: "http", Port: 8080, Protocol: "TCP"}},
+	}
+	if serviceImportEquivalent(svc, diffPorts) {
+		t.Error("expected different ports to not be equivalent")
+	}
+}