// Example of using the global log.
func Example() {
log.SetOutput(os.Stdout)
log.SetLogLevel(log.LevelAll ^ log.LevelDebug)
// we call SetTimestamp so that the timestamp will be deterministic
log.SetTimestamp(func() string { return "2006-01-02T15:04:05.999999999Z" })
err := log.Debug("This will not be written")
if err != nil {
log.Error("Could not write DEBUG entry: %s", err)
}
log.Info("Hello %s", "world")
// Output: 2006-01-02T15:04:05.999999999Z INFO Hello world
}
func TestLog(t *testing.T) {
var buff bytes.Buffer
log.SetOutput(&buff)
log.SetLogLevel(log.LevelAll ^ log.LevelDebug ^ log.LevelFatal)
log.Debug("Hello %s", "world") // this won't get written
log.Info("%s %d", "Hello world", 1234)
log.Close() // should have no effect, because Buffer is not a WriteCloser
log.Error("%v", struct{ s string }{"Hello world"})
log.Fatal("%v", struct{ s string }{"Hello world"}) // won't trigger or write
log.Custom("TEST", "Hello world", "extra arg")
// we do Panic later
b := buff.String()
if c := strings.Count(b, "Hello"); c != 3 {
t.Errorf("Bad \"Hello\" count: %d\n%s", c, b)
}
if strings.Count(b, "DEBUG") != 0 {
t.Error("DEBUG shouldn't have been written")
}
if strings.Count(b, "INFO") != 1 {
t.Error("INFO wasn't written")
}
if strings.Count(b, "ERROR") != 1 {
t.Error("ERROR wasn't written")
}
if strings.Count(b, "FATAL") != 0 {
t.Error("FATAL shouldn't have been written")
}
if strings.Count(b, "TEST") != 1 {
t.Error("TEST wasn't written")
}
t.Log(b)
buff.Truncate(0)
log.SetLogLevel(log.LevelAll)
defer func() {
recover()
if !strings.Contains(buff.String(), "Hello world 1234") {
t.Errorf("Bad Panic() string: %s", buff.String())
}
}()
log.Panic("%s %d", "Hello world", 1234)
t.Error("Panic didn't panic")
}