fix(test): Remove uses of t.FailNow in goroutines (#1978)

It is documented as illegal to use t.FailNow in a goroutine.
Uses of require assertions call t.FailNow. This may have led to
inconsistent test results as some assertions were subject to
undefined behavior. Note that it is still allowed to call
assert assertions in goroutines.

See: https://pkg.go.dev/testing#T.FailNow

internal/servers/worker/proxy/tcp/tcp_test.go

@@ -31,10 +31,10 @@ func TestHandleTcpProxyV1(t *testing.T) {
 	defer l.Close()
 
 	var endpointConn net.Conn
+	var endpointErr error
 	ready := make(chan struct{})
 	go func() {
-		endpointConn, err = l.Accept()
-		require.NoError(err)
+		endpointConn, endpointErr = l.Accept()
 
 		defer endpointConn.Close()
 		ready <- struct{}{}
@@ -71,13 +71,20 @@ func TestHandleTcpProxyV1(t *testing.T) {
 		UserClientIp:   net.ParseIP("127.0.0.1"),
 	}
 
+	// Use error channel so that we can use test assertions on the returned error.
+	// It is illegal to call `t.FailNow()` from a goroutine.
+	// https://pkg.go.dev/testing#T.FailNow
+	errChan := make(chan error)
 	go func() {
-		err = handleProxy(ctx, conf)
-		require.NoError(err)
+		errChan <- handleProxy(ctx, conf)
 	}()
+	t.Cleanup(func() {
+		require.NoError(<-errChan)
+	})
 
 	// wait for HandleTcpProxyV1 to dial endpoint
 	<-ready
+	require.NoError(endpointErr)
 	netConn := websocket.NetConn(ctx, clientConn, websocket.MessageBinary)
 
 	// Write from endpoint to client

internal/servers/worker/proxy/testing_test.go

@@ -9,6 +9,11 @@ import (
 	"nhooyr.io/websocket"
 )
 
+type connMsg struct {
+	msg []byte
+	err error
+}
+
 func Test_TestWsConn(t *testing.T) {
 	t.Parallel()
 	require, assert := require.New(t), assert.New(t)
@@ -16,32 +21,35 @@ func Test_TestWsConn(t *testing.T) {
 	ctx, cancelCtx := context.WithCancel(context.Background())
 	clientConn, proxyConn := TestWsConn(t, ctx)
 
-	successfulRead := make(chan struct{})
+	// Use msg channel so that we can use test assertions on the returned content.
+	// It is illegal to call `t.FailNow()` from a goroutine.
+	// https://pkg.go.dev/testing#T.FailNow
+	readChan := make(chan connMsg)
 	go func() {
 		_, msg, err := proxyConn.Read(ctx)
-		require.NoError(err)
-		assert.Equal("client to proxy", string(msg))
-		successfulRead <- struct{}{}
+		readChan <- connMsg{msg, err}
 	}()
 
 	err := clientConn.Write(ctx, websocket.MessageBinary, []byte("client to proxy"))
 	require.NoError(err)
 
 	// Wait for read to verify success
-	<-successfulRead
+	msg := <-readChan
+	require.NoError(msg.err)
+	assert.Equal("client to proxy", string(msg.msg))
 
 	go func() {
 		_, msg, err := clientConn.Read(ctx)
-		require.NoError(err)
-		assert.Equal("proxy to client", string(msg))
-		successfulRead <- struct{}{}
+		readChan <- connMsg{msg, err}
 	}()
 
 	err = proxyConn.Write(ctx, websocket.MessageBinary, []byte("proxy to client"))
 	require.NoError(err)
 
 	// Wait for read to verify success
-	<-successfulRead
+	msg = <-readChan
+	require.NoError(msg.err)
+	assert.Equal("proxy to client", string(msg.msg))
 
 	cancelCtx()
 }