Merge pull request #37636 from juanvallejo/jvallejo/bugfix/print-resource-kind-when-single-resource-type

Automatic merge from submit-queue

add resource prefix to multiple items w/ same kind

**Release note**:
```release-note
release-note-none
```

This patch ensures that a resource prefix is added to multiple items of
the same kind, when using `kubectl get all`. Before, a prefix was added only
when a single item was returned on `kubectl get all`, but ignored if only a
single resource kind existed but multiple items for that kind were
returned.

**Example**
```
$ kubectl get all
No resources found.

$ kubectl create service loadbalancer testsvc1 --tcp=8080
$ kubectl get all
NAME               CLUSTER-IP       EXTERNAL-IP                     PORT(S)    AGE
svc/testsvc1       172.30.119.220   172.46.100.155,172.46.100.155   8080/TCP   1h

$ kubectl create service loadbalancer testsvc2 --tcp=8081
$ kubectl get all
NAME               CLUSTER-IP       EXTERNAL-IP                     PORT(S)    AGE
svc/testsvc1       172.30.119.220   172.46.100.155,172.46.100.155   8080/TCP   1h
svc/testsvc2       172.30.241.197   172.46.164.158,172.46.164.158   8081/TCP   1h
```

@fabianofranz

pkg/kubectl/resource/builder_test.go

@@ -1235,3 +1235,57 @@ func TestHasNames(t *testing.T) {
 		}
 	}
 }
+
+func TestMultipleTypesRequested(t *testing.T) {
+	tests := []struct {
+		args                  []string
+		expectedMultipleTypes bool
+	}{
+		{
+			args: []string{""},
+			expectedMultipleTypes: false,
+		},
+		{
+			args: []string{"all"},
+			expectedMultipleTypes: true,
+		},
+		{
+			args: []string{"rc"},
+			expectedMultipleTypes: false,
+		},
+		{
+			args: []string{"rc,pod,svc"},
+			expectedMultipleTypes: true,
+		},
+		{
+			args: []string{"rc/foo"},
+			expectedMultipleTypes: false,
+		},
+		{
+			args: []string{"rc/foo", "rc/bar"},
+			expectedMultipleTypes: false,
+		},
+		{
+			args: []string{"rc", "foo"},
+			expectedMultipleTypes: false,
+		},
+		{
+			args: []string{"rc,pod,svc", "foo"},
+			expectedMultipleTypes: true,
+		},
+		{
+			args: []string{"rc,secrets"},
+			expectedMultipleTypes: true,
+		},
+		{
+			args: []string{"rc/foo", "rc/bar", "svc/svc"},
+			expectedMultipleTypes: true,
+		},
+	}
+	for _, test := range tests {
+		hasMultipleTypes := MultipleTypesRequested(test.args)
+		if hasMultipleTypes != test.expectedMultipleTypes {
+			t.Errorf("expected HasName to return %v for %s", test.expectedMultipleTypes, test.args)
+		}
+	}
+}