test: added TestNewConfigurationEmptyNodeList: chk for empty nodes

This just adds a check that it will fail to pass an empty node list.

config_test.go

@@ -2,6 +2,7 @@ package gorums_test
 
 import (
 	"context"
+	"errors"
 	"sync"
 	"testing"
 
@@ -10,6 +11,18 @@ import (
 	"github.com/relab/gorums/tests/dummy"
 )
 
+func TestNewConfigurationEmptyNodeList(t *testing.T) {
+	wantErr := errors.New("config: missing required node addresses")
+	mgr := gorums.NewRawManager(gorums.WithNoConnect())
+	_, err := gorums.NewRawConfiguration(mgr, gorums.WithNodeList([]string{}))
+	if err == nil {
+		t.Fatalf("Expected error, got: %v, want: %v", err, wantErr)
+	}
+	if err.Error() != wantErr.Error() {
+		t.Errorf("Error = %q, expected %q", err.Error(), wantErr)
+	}
+}
+
 func TestNewConfigurationNodeList(t *testing.T) {
 	mgr := gorums.NewRawManager(gorums.WithNoConnect())
 	cfg, err := gorums.NewRawConfiguration(mgr, gorums.WithNodeList(nodes))