feat(netxmocks): implement mocks for netxlite.Resolver (#398)

While there, make sure we require using &netxmocks.Dialer.

Still part of https://github.com/ooni/probe/issues/1505

internal/engine/legacy/netx/emitterdialer_test.go

@@ -20,7 +20,7 @@ func TestEmitterFailure(t *testing.T) {
 		Beginning: time.Now(),
 		Handler:   saver,
 	})
-	d := EmitterDialer{Dialer: netxmocks.Dialer{
+	d := EmitterDialer{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return nil, io.EOF
 		},
@@ -69,7 +69,7 @@ func TestEmitterSuccess(t *testing.T) {
 		Beginning: time.Now(),
 		Handler:   saver,
 	})
-	d := EmitterDialer{Dialer: netxmocks.Dialer{
+	d := EmitterDialer{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return &netxmocks.Conn{
 				MockRead: func(b []byte) (int, error) {

internal/engine/netx/dialer/bytecounter_test.go

@@ -76,7 +76,7 @@ func TestByteCounterNoHandlers(t *testing.T) {
 }
 
 func TestByteCounterConnectFailure(t *testing.T) {
-	dialer := &byteCounterDialer{Dialer: netxmocks.Dialer{
+	dialer := &byteCounterDialer{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return nil, io.EOF
 		},

internal/engine/netx/dialer/errorwrapper_test.go

@@ -13,7 +13,7 @@ import (
 
 func TestErrorWrapperFailure(t *testing.T) {
 	ctx := context.Background()
-	d := &errorWrapperDialer{Dialer: netxmocks.Dialer{
+	d := &errorWrapperDialer{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return nil, io.EOF
 		},
@@ -43,7 +43,7 @@ func errorWrapperCheckErr(t *testing.T, err error, op string) {
 
 func TestErrorWrapperSuccess(t *testing.T) {
 	ctx := context.Background()
-	d := &errorWrapperDialer{Dialer: netxmocks.Dialer{
+	d := &errorWrapperDialer{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return &netxmocks.Conn{
 				MockRead: func(b []byte) (int, error) {

internal/engine/netx/dialer/proxy_test.go

@@ -14,7 +14,7 @@ import (
 func TestProxyDialerDialContextNoProxyURL(t *testing.T) {
 	expected := errors.New("mocked error")
 	d := &proxyDialer{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				return nil, expected
 			},
@@ -45,7 +45,7 @@ func TestProxyDialerDialContextInvalidScheme(t *testing.T) {
 func TestProxyDialerDialContextWithEOF(t *testing.T) {
 	const expect = "10.0.0.1:9050"
 	d := &proxyDialer{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				if address != expect {
 					return nil, errors.New("unexpected address")

internal/engine/netx/dialer/saver_test.go

@@ -17,7 +17,7 @@ func TestSaverDialerFailure(t *testing.T) {
 	expected := errors.New("mocked error")
 	saver := &trace.Saver{}
 	dlr := &saverDialer{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				return nil, expected
 			},
@@ -59,7 +59,7 @@ func TestSaverConnDialerFailure(t *testing.T) {
 	expected := errors.New("mocked error")
 	saver := &trace.Saver{}
 	dlr := &saverConnDialer{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				return nil, expected
 			},
@@ -79,7 +79,7 @@ func TestSaverConnDialerSuccess(t *testing.T) {
 	saver := &trace.Saver{}
 	dlr := &saverConnDialer{
 		Dialer: &saverDialer{
-			Dialer: netxmocks.Dialer{
+			Dialer: &netxmocks.Dialer{
 				MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 					return &netxmocks.Conn{
 						MockRead: func(b []byte) (int, error) {

internal/netxlite/dialer_test.go

@@ -69,7 +69,7 @@ func (r MockableResolver) Address() string {
 }
 
 func TestDialerResolverDialForSingleIPFails(t *testing.T) {
-	dialer := &DialerResolver{Dialer: netxmocks.Dialer{
+	dialer := &DialerResolver{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return nil, io.EOF
 		},
@@ -85,7 +85,7 @@ func TestDialerResolverDialForSingleIPFails(t *testing.T) {
 
 func TestDialerResolverDialForManyIPFails(t *testing.T) {
 	dialer := &DialerResolver{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				return nil, io.EOF
 			},
@@ -102,7 +102,7 @@ func TestDialerResolverDialForManyIPFails(t *testing.T) {
 }
 
 func TestDialerResolverDialForManyIPSuccess(t *testing.T) {
-	dialer := &DialerResolver{Dialer: netxmocks.Dialer{
+	dialer := &DialerResolver{Dialer: &netxmocks.Dialer{
 		MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 			return &netxmocks.Conn{
 				MockClose: func() error {
@@ -125,7 +125,7 @@ func TestDialerResolverDialForManyIPSuccess(t *testing.T) {
 
 func TestDialerLoggerFailure(t *testing.T) {
 	d := &DialerLogger{
-		Dialer: netxmocks.Dialer{
+		Dialer: &netxmocks.Dialer{
 			MockDialContext: func(ctx context.Context, network string, address string) (net.Conn, error) {
 				return nil, io.EOF
 			},

internal/netxmocks/dialer.go

@@ -16,8 +16,8 @@ type Dialer struct {
 }
 
 // DialContext implements Dialer.DialContext.
-func (d Dialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
+func (d *Dialer) DialContext(ctx context.Context, network, address string) (net.Conn, error) {
 	return d.MockDialContext(ctx, network, address)
 }
 
-var _ dialer = Dialer{}
+var _ dialer = &Dialer{}

internal/netxmocks/resolver.go

@@ -0,0 +1,34 @@
+package netxmocks
+
+import "context"
+
+// resolver is the interface we expect from a resolver
+type resolver interface {
+	LookupHost(ctx context.Context, domain string) ([]string, error)
+	Network() string
+	Address() string
+}
+
+// Resolver is a mockable Resolver.
+type Resolver struct {
+	MockLookupHost func(ctx context.Context, domain string) ([]string, error)
+	MockNetwork    func() string
+	MockAddress    func() string
+}
+
+// LookupHost implements Resolver.LookupHost.
+func (r *Resolver) LookupHost(ctx context.Context, domain string) ([]string, error) {
+	return r.MockLookupHost(ctx, domain)
+}
+
+// Address implements Resolver.Address.
+func (r *Resolver) Address() string {
+	return r.MockAddress()
+}
+
+// Network implements Resolver.Network.
+func (r *Resolver) Network() string {
+	return r.MockNetwork()
+}
+
+var _ resolver = &Resolver{}

internal/netxmocks/resolver_test.go

@@ -0,0 +1,46 @@
+package netxmocks
+
+import (
+	"context"
+	"errors"
+	"testing"
+)
+
+func TestResolverLookupHost(t *testing.T) {
+	expected := errors.New("mocked error")
+	r := &Resolver{
+		MockLookupHost: func(ctx context.Context, domain string) ([]string, error) {
+			return nil, expected
+		},
+	}
+	ctx := context.Background()
+	addrs, err := r.LookupHost(ctx, "dns.google")
+	if !errors.Is(err, expected) {
+		t.Fatal("unexpected error", err)
+	}
+	if addrs != nil {
+		t.Fatal("expected nil addr")
+	}
+}
+
+func TestResolverNetwork(t *testing.T) {
+	r := &Resolver{
+		MockNetwork: func() string {
+			return "antani"
+		},
+	}
+	if v := r.Network(); v != "antani" {
+		t.Fatal("unexpected network", v)
+	}
+}
+
+func TestResolverAddress(t *testing.T) {
+	r := &Resolver{
+		MockAddress: func() string {
+			return "1.1.1.1"
+		},
+	}
+	if v := r.Address(); v != "1.1.1.1" {
+		t.Fatal("unexpected address", v)
+	}
+}