qmk-rgb/cmd/qmk-rgb-tool/arity_test.go

package main

import (
	"strings"
	"testing"

	"github.com/spf13/cobra"
)

// `info`, `enable`, `disable` and `list` take nothing. Without a declared
// arity cobra applies arbitraryArgs, so a stray token yielded exit 0 and the
// command looked like it had done its work — a caller could believe a
// lighting change happened when the argument was silently dropped.
func TestZeroArgCommandsRejectStrayTokens(t *testing.T) {
	cmds := map[string]*cobra.Command{
		"info":    NewInfoCmd(),
		"enable":  NewEnableCmd(),
		"disable": NewDisableCmd(),
		"list":    NewProfileListCmd(),
	}

	for name, cmd := range cmds {
		t.Run(name, func(t *testing.T) {
			err := cmd.ValidateArgs([]string{"unexpected-arg"})
			if err == nil {
				t.Errorf("%s accepted an argument, want it rejected", name)
				return
			}
			if !strings.Contains(err.Error(), "unexpected-arg") {
				t.Errorf("%s error = %q, want it to name the offending argument", name, err)
			}
		})
	}
}

// Rejecting extras must not break the no-argument case.
func TestZeroArgCommandsAcceptNoArgs(t *testing.T) {
	cmds := map[string]*cobra.Command{
		"info":    NewInfoCmd(),
		"enable":  NewEnableCmd(),
		"disable": NewDisableCmd(),
		"list":    NewProfileListCmd(),
	}

	for name, cmd := range cmds {
		t.Run(name, func(t *testing.T) {
			if err := cmd.ValidateArgs(nil); err != nil {
				t.Errorf("%s rejected the empty argument list: %v", name, err)
			}
		})
	}
}

// Commands that do take an argument must keep accepting exactly one.
func TestOneArgCommandsKeepTheirArity(t *testing.T) {
	cmds := map[string]*cobra.Command{
		"brightness": NewBrightnessCmd(),
		"speed":      NewSpeedCmd(),
		"color":      NewColorCmd(),
	}

	for name, cmd := range cmds {
		t.Run(name, func(t *testing.T) {
			if err := cmd.ValidateArgs([]string{"160"}); err != nil {
				t.Errorf("%s rejected its argument: %v", name, err)
			}
			if err := cmd.ValidateArgs([]string{"1", "2"}); err == nil {
				t.Errorf("%s accepted two arguments, want exactly one", name)
			}
		})
	}
}