Not able to build go package for debugging in vscode

Recently I have updated go debugger to dlv-dap and now I have problems debugging go packages. This is my file structure:

File contents:

main.go

package main

import (
    "debugger_test/packageA"
    "fmt"
)

func main() {
    res := packageA.DoStuff(5)
    fmt.Println(res)
}

fileA.go

package packageA

func DoStuff(a int) int {
    temp := a*a - 30
    return temp
}

fileA_test.go

package packageA

import (
    "testing"

    "github.com/stretchr/testify/assert"
)

func TestStuff(t *testing.T) {
    arg := 2
    res := DoStuff(arg)
    assert.Equal(t, -26, res)
}

launch.json:

    "version": "0.2.0",
    "configurations": [
        {
            "name": "Test",
            "type": "go",
            "request": "launch",
            "mode": "test",
            "program": "${fileDirname}",
            "substitutePath": [
                {
                    "from": "/home/vlasov",
                    "to": "/opt/storage",
                },
            ],
        },
        {
            "name": "Main",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "program": "${fileDirname}",
            "substitutePath": [
                {
                    "from": "/home/vlasov",
                    "to": "/opt/storage",
                },
            ],
        }
    ]
}

This used to work just fine before dlv-dap. Now when I try to debug I get this message:

Starting: /home/vlasov/go/bin/dlv-dap dap --listen=127.0.0.1:46369 --log-dest=3
DAP server listening at: 127.0.0.1:46369
Build Error: go test -c -o /opt/storage/debugger_test/packageA/__debug_bin -gcflags all=-N -l /home/vlasov/debugger_test/packageA
directory /home/vlasov/debugger_test/packageA outside available modules (exit status 1)

A partial fix I was able to find is to change ${fileDirname} to ${fileDirname}/main.go, however this way debugger does not hit breakpoints in main.go. This method does not work for tests, I still get similar message with "program": "${fileDirname}/fileA_test.go".

What is the correct way to configure launch.json to be able to run debug tests and packages normally?