fakeio is a small library to fake stdout/stderr/stdin.
This is mainly for unit testing of CLI applications. Please see documentation
for more details.
$ go get github.com/rhysd/go-fakeio
Basic usage:
import (
"bufio"
"github.com/rhysd/go-fakeio"
)
// Fake stdout and input 'hello' to stdin
fake := fakeio.Stdout().Stdin("hello!")
defer fake.Restore()
// Do something...
// "hello!" is stored to variable `i`
i, err := bufio.NewReader(os.Stdin).ReadString('!')
// At this point, this line outputs nothing
fmt.Print("bye")
// "bye" is stored to variable `o`
o, err := fake.String()Faking stderr:
fake := fakeio.Stderr()
defer fake.Restore()Faking stdin:
fake, err := fakeio.Stdin("hello")
defer fake.Restore()Faking stderr/stdout/stdin
fake := fakeio.Stderr().Stdout().Stdin("Faked input to stdin")
defer fake.Restore()Reading as string:
s, err := fake.String()
if err != nil {
// Faking IO failed
panic(err)
}
fmt.Println(s)Reading as bytes:
b, err := fake.Bytes()
if err != nil {
// Faking IO failed
panic(err)
}
fmt.Println(b)Reading via io.Reader interface:
s := bufio.NewScanner(fake)
for s.Scan() {
// Reading line by line
line := s.Text()
fmt.Println(line)
}
if s.Err() != nil {
// Error happened while reading
panic(s.Err)
}.Do() is a shortcut
s, err := fakeio.Stderr().Stdout().Do(func () {
// Do something
// Faked stderr and stdout are restored at exit of this scope
})
if err != nil {
// Faking IO failed
panic(err)
}
fmt.Println(s)Please see examples for actual examples.