Golang: tests and working directory

Question

I'm writing some unit tests for my application in Go. The tests fail however because it cannot find the configuration files. Normally the binary looks for the configuration files in the working directory under the path conf/*.conf.

I figured that browsing to the directory that has conf/ and running go test in it would solve it, but it still reports that the file system cannot find the path specified.

How can I tell go test to use a certain directory as the working directory so that the tests may actually be executed?

Solution 1

You may be able to use the Caller to get the path to the current test source file, like this:

package sample

import (
    "testing"
    "runtime"
    "fmt"
)

func TestGetFilename(t *testing.T) {
    _, filename, _, _ := runtime.Caller(0)
    t.Logf("Current test filename: %s", filename)
}

Solution 2

I do not believe this is possible. I have not been able to find documentation stating this explicitly, but I believe go test always uses the package directory (containing the go source files) as the working directory.

Solution 3

As a workaround, I compiled the test and execute the test from the current directory.

go test -c && ./<mypackage>.test

Or, if you want a generic command that you can use, you can rename the test file with -o option.

go test -c -o xyz.test && ./xyz.test

Solution 4

No matter where the work directory is. It must be under your project Dir. So my solution is

wd, _ := os.Getwd()
for !strings.HasSuffix(wd, "<yourProjectDirName>") {
    wd = filepath.Dir(wd)
}

raw, err := ioutil.ReadFile(fmt.Sprintf("%s/src/conf/conf.dev.json", wd))

Your path should always start from your project Dir. Every time you read the file in a package and accessed by main.go or your another package unit test. It will always work.

Solution 5

While not really convenient, you can always pass it as a command line variable, for example :

package blah_test

import (
    "flag"
    "fmt"
    "os"
    "testing"
)

var (
    cwd_arg = flag.String("cwd", "", "set cwd")
)

func init() {
    flag.Parse()
    if *cwd_arg != "" {
        if err := os.Chdir(*cwd_arg); err != nil {
            fmt.Println("Chdir error:", err)
        }
    }
}

func TestBlah(t *testing.T) {
    t.Errorf("cwd: %+q", *cwd_arg)
}

Then run it like :

┌─ oneofone@Oa [/tmp]                                                                                             
└──➜ go test . -cwd="$PWD"
--- FAIL: TestBlah (0.00 seconds)
        blah_test.go:16: cwd: "/tmp"

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Comments

[Jesse Brands]

Thanks, that's very annoying but I suppose there's no way around it. I'll probably add a bug report/suggestion to the Go project to perhaps add a -w $d or --working-dir=$d parameter to go test.

[Jesse Brands]

That's a good idea. I'm curious though, what command prompt is that you're using?

[OneOfOne]

I'm using fish, the specific function to show the prompt is @ github.com/OneOfOne/etc-fish/blob/master/functions/…

[Yobert]

Agreed, this is a very nice way to to do it. Combine with the Dir function from package "path/filepath" to build a path relative the input go file's folder.

[Ralph]

Unfortunately, this does not seem to work when the source code contains *template.Must(...) calls to compile HTML templates.

[DivinesLight]

This is the best answer for me! I could run my tests from the same dir where my binary usually runs from.

[m90]

This is very nice, but won't work if you have the (pretty common) pattern of using pkgname/cmd/pkgname.

[Dr. Jan-Philip Gehrcke]

There should absolutely be some documentation here -- hopefully it's actually a guarantee :).

[craigster0]

I had assumed that go ran the tests in the same directory as the source code being tested, but at least as of go version 1.15.5, the tests are compiled in a temporary directory under /tmp (e.g. /tmp/go-build549268541) and with a working directory of /tmp. So os.Chdir("..") will not work anymore. the answer using runtime.Caller(0) seems like the way to go.

[Simon Kohlmeyer]

Note that Caller retuns the package name if the tests are run using go test github.com/the/package. I'm trying to package a go application for nixpkgs and this is giving me some trouble.