What is the URL of the page with the issue?

https://go.dev/doc/tutorial/add-a-test

What is your user agent?

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36

Screenshot

This is an issue with the result of running the tutorial code locally, not with the tutorial page itself, so a screenshot wouldn't be useful here.

What did you do?

  1. Follow the "Create a Go Module" tutorial from the beginning to Step 6: Add a test.
  2. In Step 4 ("Break the greetings.Hello function to view a failing test."), make the breaking change.
  3. Perform Step 5 (run go test)

To make this easier for you to reproduce, I am attaching a .zip containing the code up to this point in the tutorial that is reproducing the issue on my machine: create-a-go-module.zip.

What did you expect to see?

The test failure described in Step 5:

$ go test
--- FAIL: TestHelloName (0.00s)
    greetings_test.go:15: Hello("Gladys") = "Hail, %v! Well met!", <nil>, want match for `\bGladys\b`, nil
FAIL
exit status 1
FAIL    example.com/greetings   0.182s

What did you see instead?

$ go test
# example.com/greetings
# [example.com/greetings]
./greetings.go:17:25: non-constant format string in call to fmt.Sprintf
FAIL    example.com/greetings [build failed]

I think the tutorial's recommended breaking change is now blocked by go vet from https://github.com/golang/go/issues/60529, which landed in 1.24 (I am using 1.24.5).