add several subcommand unittests

parse.go

@@ -292,7 +292,6 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) {
 
 					cmd.subcommands = append(cmd.subcommands, subcmd)
 					isSubcommand = true
-					fmt.Println("found a subcommand")
 				default:
 					errs = append(errs, fmt.Sprintf("unrecognized tag '%s' on field %s", key, tag))
 					return false
@@ -335,8 +334,6 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) {
 		return nil, fmt.Errorf("%T cannot have both subcommands and positional arguments", t)
 	}
 
-	fmt.Printf("parsed a command with %d subcommands\n", len(cmd.subcommands))
-
 	return &cmd, nil
 }
 
@@ -434,7 +431,6 @@ func (p *Parser) process(args []string) error {
 
 		if !isFlag(arg) || allpositional {
 			// each subcommand can have either subcommands or positionals, but not both
-			fmt.Printf("processing %q, with %d subcommands", arg, len(curCmd.subcommands))
 			if len(curCmd.subcommands) == 0 {
 				positionals = append(positionals, arg)
 				continue

subcommand_test.go

@@ -45,3 +45,118 @@ func TestMinimalSubcommand(t *testing.T) {
 	require.NoError(t, err)
 	assert.NotNil(t, args.List)
 }
+
+func TestNamedSubcommand(t *testing.T) {
+	type listCmd struct {
+	}
+	var args struct {
+		List *listCmd `arg:"subcommand:ls"`
+	}
+	err := parse("ls", &args)
+	require.NoError(t, err)
+	assert.NotNil(t, args.List)
+}
+
+func TestEmptySubcommand(t *testing.T) {
+	type listCmd struct {
+	}
+	var args struct {
+		List *listCmd `arg:"subcommand"`
+	}
+	err := parse("", &args)
+	require.NoError(t, err)
+	assert.Nil(t, args.List)
+}
+
+func TestTwoSubcommands(t *testing.T) {
+	type getCmd struct {
+	}
+	type listCmd struct {
+	}
+	var args struct {
+		Get  *getCmd  `arg:"subcommand"`
+		List *listCmd `arg:"subcommand"`
+	}
+	err := parse("list", &args)
+	require.NoError(t, err)
+	assert.Nil(t, args.Get)
+	assert.NotNil(t, args.List)
+}
+
+func TestSubcommandsWithOptions(t *testing.T) {
+	type getCmd struct {
+		Name string
+	}
+	type listCmd struct {
+		Limit int
+	}
+	type cmd struct {
+		Verbose bool
+		Get     *getCmd  `arg:"subcommand"`
+		List    *listCmd `arg:"subcommand"`
+	}
+
+	{
+		var args cmd
+		err := parse("list", &args)
+		require.NoError(t, err)
+		assert.Nil(t, args.Get)
+		assert.NotNil(t, args.List)
+	}
+
+	{
+		var args cmd
+		err := parse("list --limit 3", &args)
+		require.NoError(t, err)
+		assert.Nil(t, args.Get)
+		assert.NotNil(t, args.List)
+		assert.Equal(t, args.List.Limit, 3)
+	}
+
+	{
+		var args cmd
+		err := parse("list --limit 3 --verbose", &args)
+		require.NoError(t, err)
+		assert.Nil(t, args.Get)
+		assert.NotNil(t, args.List)
+		assert.Equal(t, args.List.Limit, 3)
+		assert.True(t, args.Verbose)
+	}
+
+	{
+		var args cmd
+		err := parse("list --verbose --limit 3", &args)
+		require.NoError(t, err)
+		assert.Nil(t, args.Get)
+		assert.NotNil(t, args.List)
+		assert.Equal(t, args.List.Limit, 3)
+		assert.True(t, args.Verbose)
+	}
+
+	{
+		var args cmd
+		err := parse("--verbose list --limit 3", &args)
+		require.NoError(t, err)
+		assert.Nil(t, args.Get)
+		assert.NotNil(t, args.List)
+		assert.Equal(t, args.List.Limit, 3)
+		assert.True(t, args.Verbose)
+	}
+
+	{
+		var args cmd
+		err := parse("get", &args)
+		require.NoError(t, err)
+		assert.NotNil(t, args.Get)
+		assert.Nil(t, args.List)
+	}
+
+	{
+		var args cmd
+		err := parse("get --name test", &args)
+		require.NoError(t, err)
+		assert.NotNil(t, args.Get)
+		assert.Nil(t, args.List)
+		assert.Equal(t, args.Get.Name, "test")
+	}
+}