cleanup(netx): remove subpackages and unnecessary code (#788)

This pull request consists of several small and obvious cleanups in the netx directory.

See https://github.com/ooni/probe/issues/2121

internal/engine/netx/integration_test.go

@@ -1,89 +0,0 @@
-package netx_test
-
-import (
-	"context"
-	"errors"
-	"net/http"
-	"testing"
-
-	"github.com/apex/log"
-	"github.com/ooni/probe-cli/v3/internal/bytecounter"
-	"github.com/ooni/probe-cli/v3/internal/engine/netx"
-	"github.com/ooni/probe-cli/v3/internal/netxlite"
-	"github.com/ooni/probe-cli/v3/internal/tracex"
-)
-
-func TestSuccess(t *testing.T) {
-	if testing.Short() {
-		t.Skip("skip test in short mode")
-	}
-	log.SetLevel(log.DebugLevel)
-	counter := bytecounter.New()
-	config := netx.Config{
-		BogonIsError:        true,
-		ByteCounter:         counter,
-		CacheResolutions:    true,
-		ContextByteCounting: true,
-		DialSaver:           &tracex.Saver{},
-		HTTPSaver:           &tracex.Saver{},
-		Logger:              log.Log,
-		ReadWriteSaver:      &tracex.Saver{},
-		ResolveSaver:        &tracex.Saver{},
-		TLSSaver:            &tracex.Saver{},
-	}
-	txp := netx.NewHTTPTransport(config)
-	client := &http.Client{Transport: txp}
-	resp, err := client.Get("https://www.google.com")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if _, err = netxlite.ReadAllContext(context.Background(), resp.Body); err != nil {
-		t.Fatal(err)
-	}
-	if err = resp.Body.Close(); err != nil {
-		t.Fatal(err)
-	}
-	if counter.Sent.Load() <= 0 {
-		t.Fatal("no bytes sent?!")
-	}
-	if counter.Received.Load() <= 0 {
-		t.Fatal("no bytes received?!")
-	}
-	if ev := config.DialSaver.Read(); len(ev) <= 0 {
-		t.Fatal("no dial events?!")
-	}
-	if ev := config.HTTPSaver.Read(); len(ev) <= 0 {
-		t.Fatal("no HTTP events?!")
-	}
-	if ev := config.ReadWriteSaver.Read(); len(ev) <= 0 {
-		t.Fatal("no R/W events?!")
-	}
-	if ev := config.ResolveSaver.Read(); len(ev) <= 0 {
-		t.Fatal("no resolver events?!")
-	}
-	if ev := config.TLSSaver.Read(); len(ev) <= 0 {
-		t.Fatal("no TLS events?!")
-	}
-}
-
-func TestBogonResolutionNotBroken(t *testing.T) {
-	saver := new(tracex.Saver)
-	r := netx.NewResolver(netx.Config{
-		BogonIsError: true,
-		DNSCache: map[string][]string{
-			"www.google.com": {"127.0.0.1"},
-		},
-		ResolveSaver: saver,
-		Logger:       log.Log,
-	})
-	addrs, err := r.LookupHost(context.Background(), "www.google.com")
-	if !errors.Is(err, netxlite.ErrDNSBogon) {
-		t.Fatal("not the error we expected")
-	}
-	if err.Error() != netxlite.FailureDNSBogonError {
-		t.Fatal("error not correctly wrapped")
-	}
-	if len(addrs) > 0 {
-		t.Fatal("expected no addresses here")
-	}
-}