Unit test unknown value in config

pkg/cloudprovider/providers/gce/gce.go

@@ -198,11 +198,11 @@ func newGCECloud(config io.Reader) (*GCECloud, error) {
 	var nodeTags []string
 	var nodeInstancePrefix string
 	if config != nil {
-		var cfg Config
-		if err := gcfg.FatalOnly(gcfg.ReadInto(&cfg, config)); err != nil {
-			glog.Errorf("Couldn't read config: %v", err)
+		cfg, err := readConfig(config)
+		if err != nil {
 			return nil, err
 		}
+
 		glog.Infof("Using GCE provider config %+v", cfg)
 		if cfg.Global.ApiEndpoint != "" {
 			apiEndpoint = cfg.Global.ApiEndpoint
@@ -241,6 +241,15 @@ func newGCECloud(config io.Reader) (*GCECloud, error) {
 		nodeTags, nodeInstancePrefix, tokenSource, true /* useMetadataServer */)
 }
 
+func readConfig(reader io.Reader) (*Config, error) {
+	cfg := &Config{}
+	if err := gcfg.FatalOnly(gcfg.ReadInto(cfg, reader)); err != nil {
+		glog.Errorf("Couldn't read config: %v", err)
+		return nil, err
+	}
+	return cfg, nil
+}
+
 // Creates a GCECloud object using the specified parameters.
 // If no networkUrl is specified, loads networkName via rest call.
 // If no tokenSource is specified, uses oauth2.DefaultTokenSource.

pkg/cloudprovider/providers/gce/gce_test.go

@@ -18,9 +18,26 @@ package gce
 
 import (
 	"reflect"
+	"strings"
 	"testing"
 )
 
+func TestExtraKeyInConfig(t *testing.T) {
+	const s = `[Global]
+project-id = my-project
+unknown-key = abc
+network-name = my-network
+   `
+	reader := strings.NewReader(s)
+	config, err := readConfig(reader)
+	if err != nil {
+		t.Fatalf("Unexpected config parsing error %v", err)
+	}
+	if config.Global.ProjectID != "my-project" || config.Global.NetworkName != "my-network" {
+		t.Fatalf("Expected config values to continue to be read despite extra key-value pair.")
+	}
+}
+
 func TestGetRegion(t *testing.T) {
 	zoneName := "us-central1-b"
 	regionName, err := GetGCERegion(zoneName)