package inetwork

import (
    "net"
    "testing"
)

func TestGetIpAddress(t *testing.T) {
    netInterfaces = func() ([]net.Interface, error) {
        // I can create net.Interface{}, but I can't redefine
        // method `Addrs` on net.Interface

        return []net.Interface{}, nil
    }

    address, err := GetIpAddress()
    if err != nil {
        t.Errorf("GetIpAddress: error = %v", err)
    }

    if address == nil {
        t.Errorf("GetIpAddress: errror = address ip is nil")
    }
}