github.com/mvdan/u-root-coreutils@v0.0.0-20230122170626-c2eef2898555/cmds/core/tee/tee_test.go

// Copyright 2022 the u-root Authors. All rights reserved
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"bytes"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestTee(t *testing.T) {
	tests := []struct {
		name          string
		input         string
		args          []string
		append        bool
		appendContent string
	}{
		{
			name:  "default tee",
			input: "hello",
			args:  []string{"a1", "a2"},
		},
		{
			name:          "with append flag",
			input:         "a\nb\n",
			args:          []string{"b1"},
			append:        true,
			appendContent: "hello",
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			tempDir := t.TempDir()

			for i := 0; i < len(test.args); i++ {
				test.args[i] = filepath.Join(tempDir, test.args[i])
			}

			if test.append {
				for _, arg := range test.args {
					err := os.WriteFile(arg, []byte(test.appendContent), 0666)
					if err != nil {
						t.Fatal(err)
					}
				}
			}

			var stdout bytes.Buffer
			var stderr bytes.Buffer
			cmd := newCommand(test.append, false, test.args)
			cmd.stdin = strings.NewReader(test.input)
			cmd.stdout = &stdout
			cmd.stderr = &stderr
			if err := cmd.run(); err != nil {
				t.Fatal(err)
			}

			// test if stdin match stdout
			if test.input != stdout.String() {
				t.Errorf("wanted: %q, got: %q", test.input, stdout.String())
			}

			for _, name := range test.args {
				b, err := os.ReadFile(name)
				if err != nil {
					t.Error(err)
				}
				res := string(b)
				expectedContent := test.input

				if test.append {
					expectedContent = test.appendContent + expectedContent
				}

				if res != expectedContent {
					t.Errorf("wanted: %q, got %q", expectedContent, res)
				}
			}
		})
	}
}