How to print from go test to console without using verbose option

Question

I want to print an informative message to console from a test, but not have the verbose test output.

I have tried printing from the test using:

• fmt.Println("my message") // STDOUT
• fmt.Fprintln(os.Stderr, "my message") // STDERR
• t.Log("my message\n") // testing.T log

which all produce the same effect of showing in the console if go test -v is used, but not showing if just go test is used.

However, with go test -v, I also get all the verbose test output like:

=== RUN   My_Test
--- PASS: My_Test (0.07s)

go help testflag says:

-v
    Verbose output: log all tests as they are run. Also print all
    text from Log and Logf calls even if the test succeeds.

but what I want is to not log all tests as they are run, but still print all text from Log and Logf calls even if the test succeeds

Is there a way to print a visible message from within a test, but not see the RUN and PASS messages?

Answer 1

Although this doesn't print during the test, it prints straight after, which is better than not printing at all.

Define an os.File in your test file to write messages to:

var messagesFile *os.File

func messages() *os.File {
    if messagesFile == nil {
        messagesFile, _ = os.Create("tests.out")
    }
    return messagesFile
}

os.Create creates a new file if one doesn't exist, otherwise truncates the existing file.

Within your tests, write messages to that file:

messages().WriteString("my message")

Run your tests using go test, then cat the file. In my case, I use make:

test:
    go test .
    @cat tests.out

Output looks like:

ok  <path to tests>
my message