@safe unittest{    import std.socket;     InternetHost ih = new InternetHost;     ih.getHostByAddr(0x7F_00_00_01);    assert(ih.addrList[0] == 0x7F_00_00_01);    ih.getHostByAddr("127.0.0.1");    assert(ih.addrList[0] == 0x7F_00_00_01);     if (!ih.getHostByName("www.digitalmars.com"))        return;             // don't fail if not connected to internet     assert(ih.addrList.length);    InternetAddress ia = new InternetAddress(ih.addrList[0], InternetAddress.PORT_ANY);    assert(ih.name == "www.digitalmars.com" || ih.name == "digitalmars.com",            ih.name);     /* The following assert randomly fails in the test suite.     * https://issues.dlang.org/show_bug.cgi?id=22791     * So just ignore it when it fails.     */    //assert(ih.getHostByAddr(ih.addrList[0]));    if (ih.getHostByAddr(ih.addrList[0]))    {        string getHostNameFromInt = ih.name.dup;         // This randomly fails in the compiler test suite        //assert(ih.getHostByAddr(ia.toAddrString()));         if (ih.getHostByAddr(ia.toAddrString()))        {            string getHostNameFromStr = ih.name.dup;            assert(getHostNameFromInt == getHostNameFromStr);        }    }} @system unittest{    import std.socket;         auto addr1 = new InternetAddress("127.0.0.1", 80);        auto addr2 = new InternetAddress("127.0.0.2", 80);         assert(addr1 == addr1);        assert(addr1 != addr2);    } @safe unittest{    import std.socket;     immutable ubyte[4] data = [1, 2, 3, 4];    auto pair = socketPair();    scope(exit) foreach (s; pair) s.close();     pair[0].send(data[]);     auto buf = new ubyte[data.length];    pair[1].receive(buf);    assert(buf == data);}