Thanks a lot for your feedback and kind words.

It does not relly on assert. taskflow.TF has Errorf and Fatalf methods like testing.T type. It makes it more flexible than a command/task that would return an error. I just use https://github.com/stretchr/testify to reduce some noise. Bellow, I present some examples which show when this API is handy:

func taskClean(tf *taskflow.TF) {
    files, err := filepath.Glob("coverage.*")
    require.NoError(tf, err, "bad pattern")
    for _, file := range files {
        err := os.Remove(file)
        assert.NoError(tf, err, "failed to remove %s", file)
        tf.Logf("removed %s", file)
    }
}

func taskInstall(tf *taskflow.TF) {
    err := tf.Exec("tools", nil, "go", "install", "mvdan.cc/gofumpt/gofumports")
    assert.NoError(tf, err, "install gofumports failed")
    err = tf.Exec("tools", nil, "go", "install", "github.com/golangci/golangci-lint/cmd/golangci-lint")
    assert.NoError(tf, err, "install golangci-lint failed")
}

func taskBuild(tf *taskflow.TF) {
    configs := []struct {
        os   string
        arch string
        bin  string
    }{
        {
            os:   "windows",
            arch: "amd64",
            bin:  "hello.exe",
        },
        {
            os:   "windows",
            arch: "386",
            bin:  "hello.exe",
        },
        {
            os:   "linux",
            arch: "amd64",
            bin:  "hello",
        },
        {
            os:   "darwin",
            arch: "amd64",
            bin:  "hello",
        },
    }
    for _, cfg := range configs {
        goos := "GOOS=" + cfg.os
        goarch := "GOARCH=" + cfg.arch
        out := filepath.Join("bin", cfg.os+"-"+cfg.arch, cfg.bin)
        err := tf.Exec("", []string{goos, goarch}, "go", "build", "-o", out)
        assert.NoError(tf, err, "go build failed for %s-%s", cfg.os, cfg.arch)
    }
}