refactor: move ErrorWrapperResolver to errorsx pkg (#419)

Part of https://github.com/ooni/probe/issues/1505

internal/engine/netx/resolver/errorwrapper.go

@@ -1,25 +0,0 @@
-package resolver
-
-import (
-	"context"
-
-	"github.com/ooni/probe-cli/v3/internal/errorsx"
-)
-
-// ErrorWrapperResolver is a Resolver that knows about wrapping errors.
-type ErrorWrapperResolver struct {
-	Resolver
-}
-
-// LookupHost implements Resolver.LookupHost
-func (r ErrorWrapperResolver) LookupHost(ctx context.Context, hostname string) ([]string, error) {
-	addrs, err := r.Resolver.LookupHost(ctx, hostname)
-	err = errorsx.SafeErrWrapperBuilder{
-		Classifier: errorsx.ClassifyResolveFailure,
-		Error:      err,
-		Operation:  errorsx.ResolveOperation,
-	}.MaybeBuild()
-	return addrs, err
-}
-
-var _ Resolver = ErrorWrapperResolver{}

internal/engine/netx/resolver/errorwrapper_test.go

@@ -1,45 +0,0 @@
-package resolver_test
-
-import (
-	"context"
-	"errors"
-	"testing"
-
-	"github.com/ooni/probe-cli/v3/internal/engine/netx/resolver"
-	"github.com/ooni/probe-cli/v3/internal/errorsx"
-)
-
-func TestErrorWrapperSuccess(t *testing.T) {
-	orig := []string{"8.8.8.8"}
-	r := resolver.ErrorWrapperResolver{
-		Resolver: resolver.NewFakeResolverWithResult(orig),
-	}
-	addrs, err := r.LookupHost(context.Background(), "dns.google.com")
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(addrs) != len(orig) || addrs[0] != orig[0] {
-		t.Fatal("not the result we expected")
-	}
-}
-
-func TestErrorWrapperFailure(t *testing.T) {
-	r := resolver.ErrorWrapperResolver{
-		Resolver: resolver.NewFakeResolverThatFails(),
-	}
-	ctx := context.Background()
-	addrs, err := r.LookupHost(ctx, "dns.google.com")
-	if addrs != nil {
-		t.Fatal("expected nil addr here")
-	}
-	var errWrapper *errorsx.ErrWrapper
-	if !errors.As(err, &errWrapper) {
-		t.Fatal("cannot properly cast the returned error")
-	}
-	if errWrapper.Failure != errorsx.FailureDNSNXDOMAINError {
-		t.Fatal("unexpected failure")
-	}
-	if errWrapper.Operation != errorsx.ResolveOperation {
-		t.Fatal("unexpected Operation")
-	}
-}