Expanding tests to cover Unix sockets version of client (#3132)

* Adds a random suffix to temporary Unix sockets during testing

* Adds Unix domain socket tests for client (FAILING)

This adds Unix domain socket tests for the privval client. Right now,
one of the tests (TestRemoteSignerRetry) fails, probably because the
Unix domain socket state is known instantaneously on both sides by the
OS. Committing this to collaborate on the error.

* Removes extraneous logging

* Completes testing of Unix sockets client version

This completes the testing of the client connecting via Unix sockets.
There are two specific tests (TestSocketPVDeadline and
TestRemoteSignerRetryTCPOnly) that are only relevant to TCP connections.

* Renames test to show TCP-specificity

* Adds testing into closures for consistency (forgot previously)

* Moves test specific to RemoteSigner into own file

As per discussion on #3132, `TestRemoteSignerRetryTCPOnly` doesn't
really belong with the client tests. This moves it into its own file
related to the `RemoteSigner` class.

privval/client_test.go

@@ -27,120 +27,170 @@ var (
 	testHeartbeatTimeout3o2 = 6 * time.Millisecond // 3/2 of the other one
 )
 
-func TestSocketPVAddress(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-	)
-	defer sc.Stop()
-	defer rs.Stop()
+type socketTestCase struct {
+	addr   string
+	dialer Dialer
+}
 
-	serverAddr := rs.privVal.GetPubKey().Address()
-	clientAddr := sc.GetPubKey().Address()
+func socketTestCases(t *testing.T) []socketTestCase {
+	tcpAddr := fmt.Sprintf("tcp://%s", testFreeTCPAddr(t))
+	unixFilePath, err := testUnixAddr()
+	require.NoError(t, err)
+	unixAddr := fmt.Sprintf("unix://%s", unixFilePath)
+	return []socketTestCase{
+		socketTestCase{
+			addr:   tcpAddr,
+			dialer: DialTCPFn(tcpAddr, testConnDeadline, ed25519.GenPrivKey()),
+		},
+		socketTestCase{
+			addr:   unixAddr,
+			dialer: DialUnixFn(unixFilePath),
+		},
+	}
+}
 
-	assert.Equal(t, serverAddr, clientAddr)
+func TestSocketPVAddress(t *testing.T) {
+	for _, tc := range socketTestCases(t) {
+		// Execute the test within a closure to ensure the deferred statements
+		// are called between each for loop iteration, for isolated test cases.
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			serverAddr := rs.privVal.GetPubKey().Address()
+			clientAddr := sc.GetPubKey().Address()
+
+			assert.Equal(t, serverAddr, clientAddr)
+		}()
+	}
 }
 
 func TestSocketPVPubKey(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-	)
-	defer sc.Stop()
-	defer rs.Stop()
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+			)
+			defer sc.Stop()
+			defer rs.Stop()
 
-	clientKey := sc.GetPubKey()
+			clientKey := sc.GetPubKey()
 
-	privvalPubKey := rs.privVal.GetPubKey()
+			privvalPubKey := rs.privVal.GetPubKey()
 
-	assert.Equal(t, privvalPubKey, clientKey)
+			assert.Equal(t, privvalPubKey, clientKey)
+		}()
+	}
 }
 
 func TestSocketPVProposal(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-
-		ts             = time.Now()
-		privProposal   = &types.Proposal{Timestamp: ts}
-		clientProposal = &types.Proposal{Timestamp: ts}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	require.NoError(t, rs.privVal.SignProposal(chainID, privProposal))
-	require.NoError(t, sc.SignProposal(chainID, clientProposal))
-	assert.Equal(t, privProposal.Signature, clientProposal.Signature)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+
+				ts             = time.Now()
+				privProposal   = &types.Proposal{Timestamp: ts}
+				clientProposal = &types.Proposal{Timestamp: ts}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			require.NoError(t, rs.privVal.SignProposal(chainID, privProposal))
+			require.NoError(t, sc.SignProposal(chainID, clientProposal))
+			assert.Equal(t, privProposal.Signature, clientProposal.Signature)
+		}()
+	}
 }
 
 func TestSocketPVVote(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-
-		ts    = time.Now()
-		vType = types.PrecommitType
-		want  = &types.Vote{Timestamp: ts, Type: vType}
-		have  = &types.Vote{Timestamp: ts, Type: vType}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	require.NoError(t, rs.privVal.SignVote(chainID, want))
-	require.NoError(t, sc.SignVote(chainID, have))
-	assert.Equal(t, want.Signature, have.Signature)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+
+				ts    = time.Now()
+				vType = types.PrecommitType
+				want  = &types.Vote{Timestamp: ts, Type: vType}
+				have  = &types.Vote{Timestamp: ts, Type: vType}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			require.NoError(t, rs.privVal.SignVote(chainID, want))
+			require.NoError(t, sc.SignVote(chainID, have))
+			assert.Equal(t, want.Signature, have.Signature)
+		}()
+	}
 }
 
 func TestSocketPVVoteResetDeadline(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-
-		ts    = time.Now()
-		vType = types.PrecommitType
-		want  = &types.Vote{Timestamp: ts, Type: vType}
-		have  = &types.Vote{Timestamp: ts, Type: vType}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	time.Sleep(testConnDeadline2o3)
-
-	require.NoError(t, rs.privVal.SignVote(chainID, want))
-	require.NoError(t, sc.SignVote(chainID, have))
-	assert.Equal(t, want.Signature, have.Signature)
-
-	// This would exceed the deadline if it was not extended by the previous message
-	time.Sleep(testConnDeadline2o3)
-
-	require.NoError(t, rs.privVal.SignVote(chainID, want))
-	require.NoError(t, sc.SignVote(chainID, have))
-	assert.Equal(t, want.Signature, have.Signature)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+
+				ts    = time.Now()
+				vType = types.PrecommitType
+				want  = &types.Vote{Timestamp: ts, Type: vType}
+				have  = &types.Vote{Timestamp: ts, Type: vType}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			time.Sleep(testConnDeadline2o3)
+
+			require.NoError(t, rs.privVal.SignVote(chainID, want))
+			require.NoError(t, sc.SignVote(chainID, have))
+			assert.Equal(t, want.Signature, have.Signature)
+
+			// This would exceed the deadline if it was not extended by the previous message
+			time.Sleep(testConnDeadline2o3)
+
+			require.NoError(t, rs.privVal.SignVote(chainID, want))
+			require.NoError(t, sc.SignVote(chainID, have))
+			assert.Equal(t, want.Signature, have.Signature)
+		}()
+	}
 }
 
 func TestSocketPVVoteKeepalive(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV())
-
-		ts    = time.Now()
-		vType = types.PrecommitType
-		want  = &types.Vote{Timestamp: ts, Type: vType}
-		have  = &types.Vote{Timestamp: ts, Type: vType}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	time.Sleep(testConnDeadline * 2)
-
-	require.NoError(t, rs.privVal.SignVote(chainID, want))
-	require.NoError(t, sc.SignVote(chainID, have))
-	assert.Equal(t, want.Signature, have.Signature)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewMockPV(), tc.addr, tc.dialer)
+
+				ts    = time.Now()
+				vType = types.PrecommitType
+				want  = &types.Vote{Timestamp: ts, Type: vType}
+				have  = &types.Vote{Timestamp: ts, Type: vType}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			time.Sleep(testConnDeadline * 2)
+
+			require.NoError(t, rs.privVal.SignVote(chainID, want))
+			require.NoError(t, sc.SignVote(chainID, have))
+			assert.Equal(t, want.Signature, have.Signature)
+		}()
+	}
 }
 
-func TestSocketPVDeadline(t *testing.T) {
+// TestSocketPVDeadlineTCPOnly is not relevant to Unix domain sockets, since the
+// OS knows instantaneously the state of both sides of the connection.
+func TestSocketPVDeadlineTCPOnly(t *testing.T) {
 	var (
-		addr            = testFreeAddr(t)
+		addr            = testFreeTCPAddr(t)
 		listenc         = make(chan struct{})
 		thisConnTimeout = 100 * time.Millisecond
 		sc              = newSocketVal(log.TestingLogger(), addr, thisConnTimeout)
@@ -172,218 +222,195 @@ func TestSocketPVDeadline(t *testing.T) {
 	<-listenc
 }
 
-func TestRemoteSignerRetry(t *testing.T) {
-	var (
-		attemptc = make(chan int)
-		retries  = 2
-	)
-
-	ln, err := net.Listen("tcp", "127.0.0.1:0")
-	require.NoError(t, err)
-
-	go func(ln net.Listener, attemptc chan<- int) {
-		attempts := 0
-
-		for {
-			conn, err := ln.Accept()
-			require.NoError(t, err)
-
-			err = conn.Close()
-			require.NoError(t, err)
-
-			attempts++
-
-			if attempts == retries {
-				attemptc <- attempts
-				break
-			}
-		}
-	}(ln, attemptc)
-
-	rs := NewRemoteSigner(
-		log.TestingLogger(),
-		cmn.RandStr(12),
-		types.NewMockPV(),
-		DialTCPFn(ln.Addr().String(), testConnDeadline, ed25519.GenPrivKey()),
-	)
-	defer rs.Stop()
-
-	RemoteSignerConnDeadline(time.Millisecond)(rs)
-	RemoteSignerConnRetries(retries)(rs)
-
-	assert.Equal(t, rs.Start(), ErrDialRetryMax)
-
-	select {
-	case attempts := <-attemptc:
-		assert.Equal(t, retries, attempts)
-	case <-time.After(100 * time.Millisecond):
-		t.Error("expected remote to observe connection attempts")
-	}
-}
-
 func TestRemoteSignVoteErrors(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewErroringMockPV())
-
-		ts    = time.Now()
-		vType = types.PrecommitType
-		vote  = &types.Vote{Timestamp: ts, Type: vType}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	err := sc.SignVote("", vote)
-	require.Equal(t, err.(*RemoteSignerError).Description, types.ErroringMockPVErr.Error())
-
-	err = rs.privVal.SignVote(chainID, vote)
-	require.Error(t, err)
-	err = sc.SignVote(chainID, vote)
-	require.Error(t, err)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewErroringMockPV(), tc.addr, tc.dialer)
+
+				ts    = time.Now()
+				vType = types.PrecommitType
+				vote  = &types.Vote{Timestamp: ts, Type: vType}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			err := sc.SignVote("", vote)
+			require.Equal(t, err.(*RemoteSignerError).Description, types.ErroringMockPVErr.Error())
+
+			err = rs.privVal.SignVote(chainID, vote)
+			require.Error(t, err)
+			err = sc.SignVote(chainID, vote)
+			require.Error(t, err)
+		}()
+	}
 }
 
 func TestRemoteSignProposalErrors(t *testing.T) {
-	var (
-		chainID = cmn.RandStr(12)
-		sc, rs  = testSetupSocketPair(t, chainID, types.NewErroringMockPV())
-
-		ts       = time.Now()
-		proposal = &types.Proposal{Timestamp: ts}
-	)
-	defer sc.Stop()
-	defer rs.Stop()
-
-	err := sc.SignProposal("", proposal)
-	require.Equal(t, err.(*RemoteSignerError).Description, types.ErroringMockPVErr.Error())
-
-	err = rs.privVal.SignProposal(chainID, proposal)
-	require.Error(t, err)
-
-	err = sc.SignProposal(chainID, proposal)
-	require.Error(t, err)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				chainID = cmn.RandStr(12)
+				sc, rs  = testSetupSocketPair(t, chainID, types.NewErroringMockPV(), tc.addr, tc.dialer)
+
+				ts       = time.Now()
+				proposal = &types.Proposal{Timestamp: ts}
+			)
+			defer sc.Stop()
+			defer rs.Stop()
+
+			err := sc.SignProposal("", proposal)
+			require.Equal(t, err.(*RemoteSignerError).Description, types.ErroringMockPVErr.Error())
+
+			err = rs.privVal.SignProposal(chainID, proposal)
+			require.Error(t, err)
+
+			err = sc.SignProposal(chainID, proposal)
+			require.Error(t, err)
+		}()
+	}
 }
 
 func TestErrUnexpectedResponse(t *testing.T) {
-	var (
-		addr    = testFreeAddr(t)
-		logger  = log.TestingLogger()
-		chainID = cmn.RandStr(12)
-		readyc  = make(chan struct{})
-		errc    = make(chan error, 1)
-
-		rs = NewRemoteSigner(
-			logger,
-			chainID,
-			types.NewMockPV(),
-			DialTCPFn(addr, testConnDeadline, ed25519.GenPrivKey()),
-		)
-		sc = newSocketVal(logger, addr, testConnDeadline)
-	)
-
-	testStartSocketPV(t, readyc, sc)
-	defer sc.Stop()
-	RemoteSignerConnDeadline(time.Millisecond)(rs)
-	RemoteSignerConnRetries(100)(rs)
-	// we do not want to Start() the remote signer here and instead use the connection to
-	// reply with intentionally wrong replies below:
-	rsConn, err := rs.connect()
-	defer rsConn.Close()
-	require.NoError(t, err)
-	require.NotNil(t, rsConn)
-	// send over public key to get the remote signer running:
-	go testReadWriteResponse(t, &PubKeyResponse{}, rsConn)
-	<-readyc
-
-	// Proposal:
-	go func(errc chan error) {
-		errc <- sc.SignProposal(chainID, &types.Proposal{})
-	}(errc)
-	// read request and write wrong response:
-	go testReadWriteResponse(t, &SignedVoteResponse{}, rsConn)
-	err = <-errc
-	require.Error(t, err)
-	require.Equal(t, err, ErrUnexpectedResponse)
-
-	// Vote:
-	go func(errc chan error) {
-		errc <- sc.SignVote(chainID, &types.Vote{})
-	}(errc)
-	// read request and write wrong response:
-	go testReadWriteResponse(t, &SignedProposalResponse{}, rsConn)
-	err = <-errc
-	require.Error(t, err)
-	require.Equal(t, err, ErrUnexpectedResponse)
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				logger  = log.TestingLogger()
+				chainID = cmn.RandStr(12)
+				readyc  = make(chan struct{})
+				errc    = make(chan error, 1)
+
+				rs = NewRemoteSigner(
+					logger,
+					chainID,
+					types.NewMockPV(),
+					tc.dialer,
+				)
+				sc = newSocketVal(logger, tc.addr, testConnDeadline)
+			)
+
+			testStartSocketPV(t, readyc, sc)
+			defer sc.Stop()
+			RemoteSignerConnDeadline(time.Millisecond)(rs)
+			RemoteSignerConnRetries(100)(rs)
+			// we do not want to Start() the remote signer here and instead use the connection to
+			// reply with intentionally wrong replies below:
+			rsConn, err := rs.connect()
+			defer rsConn.Close()
+			require.NoError(t, err)
+			require.NotNil(t, rsConn)
+			// send over public key to get the remote signer running:
+			go testReadWriteResponse(t, &PubKeyResponse{}, rsConn)
+			<-readyc
+
+			// Proposal:
+			go func(errc chan error) {
+				errc <- sc.SignProposal(chainID, &types.Proposal{})
+			}(errc)
+			// read request and write wrong response:
+			go testReadWriteResponse(t, &SignedVoteResponse{}, rsConn)
+			err = <-errc
+			require.Error(t, err)
+			require.Equal(t, err, ErrUnexpectedResponse)
+
+			// Vote:
+			go func(errc chan error) {
+				errc <- sc.SignVote(chainID, &types.Vote{})
+			}(errc)
+			// read request and write wrong response:
+			go testReadWriteResponse(t, &SignedProposalResponse{}, rsConn)
+			err = <-errc
+			require.Error(t, err)
+			require.Equal(t, err, ErrUnexpectedResponse)
+		}()
+	}
 }
 
-func TestRetryTCPConnToRemoteSigner(t *testing.T) {
-	var (
-		addr    = testFreeAddr(t)
-		logger  = log.TestingLogger()
-		chainID = cmn.RandStr(12)
-		readyc  = make(chan struct{})
-
-		rs = NewRemoteSigner(
-			logger,
-			chainID,
-			types.NewMockPV(),
-			DialTCPFn(addr, testConnDeadline, ed25519.GenPrivKey()),
-		)
-		thisConnTimeout = testConnDeadline
-		sc              = newSocketVal(logger, addr, thisConnTimeout)
-	)
-	// Ping every:
-	SocketValHeartbeat(testHeartbeatTimeout)(sc)
-
-	RemoteSignerConnDeadline(testConnDeadline)(rs)
-	RemoteSignerConnRetries(10)(rs)
-
-	testStartSocketPV(t, readyc, sc)
-	defer sc.Stop()
-	require.NoError(t, rs.Start())
-	assert.True(t, rs.IsRunning())
-
-	<-readyc
-	time.Sleep(testHeartbeatTimeout * 2)
-
-	rs.Stop()
-	rs2 := NewRemoteSigner(
-		logger,
-		chainID,
-		types.NewMockPV(),
-		DialTCPFn(addr, testConnDeadline, ed25519.GenPrivKey()),
-	)
-	// let some pings pass
-	time.Sleep(testHeartbeatTimeout3o2)
-	require.NoError(t, rs2.Start())
-	assert.True(t, rs2.IsRunning())
-	defer rs2.Stop()
-
-	// give the client some time to re-establish the conn to the remote signer
-	// should see sth like this in the logs:
-	//
-	// E[10016-01-10|17:12:46.128] Ping                                         err="remote signer timed out"
-	// I[10016-01-10|17:16:42.447] Re-created connection to remote signer       impl=SocketVal
-	time.Sleep(testConnDeadline * 2)
+func TestRetryConnToRemoteSigner(t *testing.T) {
+	for _, tc := range socketTestCases(t) {
+		func() {
+			var (
+				logger  = log.TestingLogger()
+				chainID = cmn.RandStr(12)
+				readyc  = make(chan struct{})
+
+				rs = NewRemoteSigner(
+					logger,
+					chainID,
+					types.NewMockPV(),
+					tc.dialer,
+				)
+				thisConnTimeout = testConnDeadline
+				sc              = newSocketVal(logger, tc.addr, thisConnTimeout)
+			)
+			// Ping every:
+			SocketValHeartbeat(testHeartbeatTimeout)(sc)
+
+			RemoteSignerConnDeadline(testConnDeadline)(rs)
+			RemoteSignerConnRetries(10)(rs)
+
+			testStartSocketPV(t, readyc, sc)
+			defer sc.Stop()
+			require.NoError(t, rs.Start())
+			assert.True(t, rs.IsRunning())
+
+			<-readyc
+			time.Sleep(testHeartbeatTimeout * 2)
+
+			rs.Stop()
+			rs2 := NewRemoteSigner(
+				logger,
+				chainID,
+				types.NewMockPV(),
+				tc.dialer,
+			)
+			// let some pings pass
+			time.Sleep(testHeartbeatTimeout3o2)
+			require.NoError(t, rs2.Start())
+			assert.True(t, rs2.IsRunning())
+			defer rs2.Stop()
+
+			// give the client some time to re-establish the conn to the remote signer
+			// should see sth like this in the logs:
+			//
+			// E[10016-01-10|17:12:46.128] Ping                                         err="remote signer timed out"
+			// I[10016-01-10|17:16:42.447] Re-created connection to remote signer       impl=SocketVal
+			time.Sleep(testConnDeadline * 2)
+		}()
+	}
 }
 
 func newSocketVal(logger log.Logger, addr string, connDeadline time.Duration) *SocketVal {
-	ln, err := net.Listen(cmn.ProtocolAndAddress(addr))
+	proto, address := cmn.ProtocolAndAddress(addr)
+	ln, err := net.Listen(proto, address)
+	logger.Info("Listening at", "proto", proto, "address", address)
 	if err != nil {
 		panic(err)
 	}
-	tcpLn := NewTCPListener(ln, ed25519.GenPrivKey())
-	TCPListenerAcceptDeadline(testAcceptDeadline)(tcpLn)
-	TCPListenerConnDeadline(testConnDeadline)(tcpLn)
-	return NewSocketVal(logger, tcpLn)
+	var svln net.Listener
+	if proto == "unix" {
+		unixLn := NewUnixListener(ln)
+		UnixListenerAcceptDeadline(testAcceptDeadline)(unixLn)
+		UnixListenerConnDeadline(connDeadline)(unixLn)
+		svln = unixLn
+	} else {
+		tcpLn := NewTCPListener(ln, ed25519.GenPrivKey())
+		TCPListenerAcceptDeadline(testAcceptDeadline)(tcpLn)
+		TCPListenerConnDeadline(connDeadline)(tcpLn)
+		svln = tcpLn
+	}
+	return NewSocketVal(logger, svln)
 }
 
 func testSetupSocketPair(
 	t *testing.T,
 	chainID string,
 	privValidator types.PrivValidator,
+	addr string,
+	dialer Dialer,
 ) (*SocketVal, *RemoteSigner) {
 	var (
-		addr    = testFreeAddr(t)
 		logger  = log.TestingLogger()
 		privVal = privValidator
 		readyc  = make(chan struct{})
@@ -391,7 +418,7 @@ func testSetupSocketPair(
 			logger,
 			chainID,
 			privVal,
-			DialTCPFn(addr, testConnDeadline, ed25519.GenPrivKey()),
+			dialer,
 		)
 
 		thisConnTimeout = testConnDeadline
@@ -429,8 +456,8 @@ func testStartSocketPV(t *testing.T, readyc chan struct{}, sc *SocketVal) {
 	}(sc)
 }
 
-// testFreeAddr claims a free port so we don't block on listener being ready.
-func testFreeAddr(t *testing.T) string {
+// testFreeTCPAddr claims a free port so we don't block on listener being ready.
+func testFreeTCPAddr(t *testing.T) string {
 	ln, err := net.Listen("tcp", "127.0.0.1:0")
 	require.NoError(t, err)
 	defer ln.Close()

privval/remote_signer_test.go

@@ -0,0 +1,68 @@
+package privval
+
+import (
+	"net"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/tendermint/tendermint/crypto/ed25519"
+	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/log"
+	"github.com/tendermint/tendermint/types"
+)
+
+// TestRemoteSignerRetryTCPOnly will test connection retry attempts over TCP. We
+// don't need this for Unix sockets because the OS instantly knows the state of
+// both ends of the socket connection. This basically causes the
+// RemoteSigner.dialer() call inside RemoteSigner.connect() to return
+// successfully immediately, putting an instant stop to any retry attempts.
+func TestRemoteSignerRetryTCPOnly(t *testing.T) {
+	var (
+		attemptc = make(chan int)
+		retries  = 2
+	)
+
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+
+	go func(ln net.Listener, attemptc chan<- int) {
+		attempts := 0
+
+		for {
+			conn, err := ln.Accept()
+			require.NoError(t, err)
+
+			err = conn.Close()
+			require.NoError(t, err)
+
+			attempts++
+
+			if attempts == retries {
+				attemptc <- attempts
+				break
+			}
+		}
+	}(ln, attemptc)
+
+	rs := NewRemoteSigner(
+		log.TestingLogger(),
+		cmn.RandStr(12),
+		types.NewMockPV(),
+		DialTCPFn(ln.Addr().String(), testConnDeadline, ed25519.GenPrivKey()),
+	)
+	defer rs.Stop()
+
+	RemoteSignerConnDeadline(time.Millisecond)(rs)
+	RemoteSignerConnRetries(retries)(rs)
+
+	assert.Equal(t, rs.Start(), ErrDialRetryMax)
+
+	select {
+	case attempts := <-attemptc:
+		assert.Equal(t, retries, attempts)
+	case <-time.After(100 * time.Millisecond):
+		t.Error("expected remote to observe connection attempts")
+	}
+}

privval/socket.go

@@ -157,7 +157,7 @@ type timeoutConn struct {
 	connDeadline time.Duration
 }
 
-// newTimeoutConn returns an instance of newTCPTimeoutConn.
+// newTimeoutConn returns an instance of timeoutConn.
 func newTimeoutConn(
 	conn net.Conn,
 	connDeadline time.Duration) *timeoutConn {

privval/socket_test.go

@@ -29,7 +29,7 @@ type listenerTestCase struct {
 // testUnixAddr will attempt to obtain a platform-independent temporary file
 // name for a Unix socket
 func testUnixAddr() (string, error) {
-	f, err := ioutil.TempFile("", "tendermint-privval-test")
+	f, err := ioutil.TempFile("", "tendermint-privval-test-*")
 	if err != nil {
 		return "", err
 	}