break out region check

main.go

@@ -173,8 +173,7 @@ func initFlags(flag *pflag.FlagSet) {
 	flag.BoolP(flagVerbose, "v", false, "Print section lines")
 }
 
-func checkConfig(v *viper.Viper) error {
-
+func checkRegion(v *viper.Viper) error {
 	region := v.GetString(flagAWSRegion)
 	if len(region) == 0 {
 		return errors.Wrap(&errInvalidRegion{Region: region}, fmt.Sprintf("%q is invalid", flagAWSRegion))
@@ -187,6 +186,16 @@ func checkConfig(v *viper.Viper) error {
 		return fmt.Errorf("%s is invalid: %w", flagAWSRegion, &errInvalidRegion{Region: region})
 	}
 
+	return nil
+}
+
+func checkConfig(v *viper.Viper) error {
+
+	err := checkRegion(v)
+	if err != nil {
+		return err
+	}
+
 	logLevel := strings.ToLower(v.GetString(flagLogLevel))
 	if len(logLevel) > 0 {
 		valid := false

main_test.go

@@ -4,6 +4,7 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
+	"testing"
 
 	"github.com/aws/aws-sdk-go/aws/endpoints"
 	"github.com/spf13/viper"
@@ -45,14 +46,14 @@ func (suite *cliTestSuite) TestCheckRegion() {
 	}
 	for _, testValue := range testValues {
 		suite.viper.Set(flagAWSRegion, testValue)
-		suite.NoError(checkConfig(suite.viper))
+		suite.NoError(checkRegion(suite.viper))
 	}
 	testValuesWithErrors := []string{
 		"AnyOtherRegionName",
 	}
 	for _, testValue := range testValuesWithErrors {
 		suite.viper.Set(flagAWSRegion, testValue)
-		suite.Error(checkConfig(suite.viper))
+		suite.Error(checkRegion(suite.viper))
 	}
 }
 
@@ -63,3 +64,7 @@ func (suite *cliTestSuite) SetViper(v *viper.Viper) {
 func (suite *cliTestSuite) SetLogger(logger *log.Logger) {
 	suite.logger = logger
 }
+
+func TestCLISuite(t *testing.T) {
+	suite.Run(t, &cliTestSuite{})
+}