console

stdin := bytes.NewBufferString("31\tred\n32\tgreen\n")

// Set up fake console with stdin, and stdout as TTY.
fake := console.Fake(
	console.WithStdin(stdin),
	console.WithStdoutTTY(true),
)

// Scan color codes and descriptions from fake stdin.
scanner := bufio.NewScanner(fake.Stdin())
for scanner.Scan() {
	var color int
	var desc string

	// Write scanned color codes to fake stdout.
	if _, err := fmt.Sscanf(scanner.Text(), "%d %s", &color, &desc); err == nil {
		fmt.Fprintf(fake.Stdout(), "\x1b[0;%dm%s\x1b[0m", color, desc)
	}
}

// Doubly escape fake stdout and write to real stdout to assert output.
stdout, _, _ := fake.Buffers()
s := strings.ReplaceAll(stdout.String(), "\x1b", `\x1b`)
fmt.Println(s)

Output:

\x1b[0;31mred\x1b[0m\x1b[0;32mgreen\x1b[0m