How to test the main package functions

Question

when you specify files on the command line, you have to specify all of them

Here’s my run:

$ ls
main.go     main_test.go
$ go test *.go
ok      command-line-arguments  0.003s

note, in my version, I ran with both main.go and main_test.go on the command line

Also, your _test file is not quite right, you need your test function to be called TestXXX and take a pointer to testing.T

Here’s the modified verison:

package main

import (
    "testing"
)

func TestFoo(t *testing.T) {
    t.Error(foo())
}

and the modified output:

$ go test *.go
--- FAIL: TestFoo (0.00s)
    main_test.go:8: Foo
FAIL
FAIL    command-line-arguments  0.003s