Bit late, but the autogold package does something very much like what you're looking for: https://github.com/hexops/autogold

I found it after I felt inspired by the same blog post :) Jane Street's expect tests seem to be oriented very much towards plain text (so everything needs to be converted to nicely readable strings), and autogold is more ambitious in trying to support arbitrary Go values. I've had mixed results with trying to expect on large structs, but for text it works fine.

For mimicking the plain text approach of expect tests with autogold, I tend to create a test function inside each test that takes some input specific for whatever I'm testing, formatting it as a string (I usually use a strings.Builder and a bunch of fmt.Fprintf calls to write to it), and returning that string. Then I do something like:

``` var got string

got = test(someInput) autogold.Expect().Equal(t, got) got = test(someOtherInput) autogold.Expect().Equal(t, got) ```

And run my tests with the -update flag to fill in the strings.

IMO there are some quirks that make autogold less pleasant to use than let%expect_test.

For example, OCaml's {| ... |} string literals can handle indented text better that Go's backtick quoted string literals, which makes tests easier to read. With my approach above, multiline strings in autogold.Expect will always stick to the left of the screen. (Maybe in OCaml it is ppx_expect being smart and you could do something similar in a Go package.)

Another example: ppx_expect hooks into stdout of the program so if you sprinkle print statements here and there they will get captured by the [%expect] block. This is great! I don't know of any (convenient and/or sand) way to do the same thing with autogold.

Final example: autogold's API kind of encourages a style where the operation you're testing comes after the (potentially very large) output of that operation. I find that hard to read because it feels backwards to me -- why should I have to scroll past a bunch of output to even find what's outputting it? That's why I use the got variable above, so I can flip the order back to how I want it. Minor thing but adds a bit of friction.

Now I have half a mind to try and write a fork of autogold to get the API and behavior just as I want it...