fix(command-args): parsing arguments correctly, add tests

cmd/main.go

@@ -27,39 +27,50 @@ var (
 	},
 		[]string{"version", "go_version", "short_hash"},
 	)
+
+	ErrNoSubCommand = errors.New("Subcommand expected. Options are `serve`, `validate`, `version` or `help`")
 )
 
 func init() {
 	prometheus.MustRegister(appInfo)
 }
 
 func main() {
-	if len(os.Args) < 2 {
-		log2.Println("Subcommand expected. Options are `serve`, `validate`, `version` or `help`")
-		os.Exit(1)
-	}
-	log2.Println("Initialized with arguments: ", os.Args)
-
-	action := strings.ToLower(os.Args[1])
-
-	flagSet := flag.NewFlagSet("", flag.ExitOnError)
-	configPath := flagSet.String("f", "./protect.yml", "Defines the path at which the configuration file can be found")
-	err := flagSet.Parse(os.Args[2:])
+	action, configPath, err := parseFlags()
 	if err != nil {
-		fmt.Printf("Error parsing flags %v\n", err)
+		log2.Println(err)
+		os.Exit(1)
 		return
 	}
 
-	log2.Println("Reading configuration from", *configPath)
+	log2.Println("Reading configuration from", configPath)
 
-	err = startup(action, *configPath)
+	err = startup(action, configPath)
 	if err != nil {
 		log2.Println("Subcommand expected. Options are `serve`, `validate`, `version` or `help`")
 		os.Exit(1)
 	}
 	os.Exit(0)
 }
 
+func parseFlags() (string, string, error) {
+	args := os.Args
+	if len(os.Args) < 2 {
+		return "", "", ErrNoSubCommand
+	}
+	log2.Println("Initialized with arguments: ", args)
+
+	action := strings.ToLower(os.Args[1])
+
+	flagSet := flag.NewFlagSet("", flag.ContinueOnError)
+	configPath := flagSet.String("f", "./protect.yml", "Defines the path at which the configuration file can be found")
+	err := flagSet.Parse(os.Args[2:])
+	if err != nil {
+		return "", "", err
+	}
+	return action, *configPath, nil
+}
+
 func startup(action string, path string) error {
 	// cfg
 	cfg, err := config.NewConfig(path)

cmd/main_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"github.com/ldebruijn/graphql-protect/internal/app/config"
 	"github.com/ldebruijn/graphql-protect/internal/business/protect"
 	"github.com/stretchr/testify/assert"
@@ -837,3 +838,67 @@ func TestMainInitialization(t *testing.T) {
 		})
 	}
 }
+
+func Test_parseFlags(t *testing.T) {
+	type args struct {
+		flags []string
+	}
+	tests := []struct {
+		name           string
+		args           args
+		wantCommand    string
+		wantConfigPath string
+		wantErr        error
+	}{
+		{
+			name: "requires a subcommand",
+			args: args{
+				flags: nil,
+			},
+			wantCommand:    "",
+			wantConfigPath: "",
+			wantErr:        ErrNoSubCommand,
+		},
+		{
+			name: "correctly picks up subcommand and uses default configpath value",
+			args: args{
+				flags: []string{"serve"},
+			},
+			wantCommand:    "serve",
+			wantConfigPath: "./protect.yml",
+			wantErr:        nil,
+		},
+		{
+			name: "correctly picks up subcommand and uses explicitly specified configpath value",
+			args: args{
+				flags: []string{"serve", "-f", "foo-bar.yml"},
+			},
+			wantCommand:    "serve",
+			wantConfigPath: "foo-bar.yml",
+			wantErr:        nil,
+		},
+		{
+			name: "correctly picks up subcommand and uses explicitly specified configpath value",
+			args: args{
+				flags: []string{"serve", "-f"},
+			},
+			wantCommand:    "",
+			wantConfigPath: "",
+			wantErr:        fmt.Errorf("flag needs an argument: -f"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			oldArgs := os.Args
+			defer func() { os.Args = oldArgs }()
+
+			os.Args = append([]string{"binary"}, tt.args.flags...)
+
+			command, configPath, err := parseFlags()
+
+			assert.Equal(t, tt.wantErr, err)
+			assert.Equalf(t, tt.wantCommand, command, "parseFlags()")
+			assert.Equalf(t, tt.wantConfigPath, configPath, "parseFlags()")
+		})
+	}
+}