fix(btcdctrl): handle & test for flaky edge-cases

1. killing a process then waiting for it can return an error depending on state, instead just exit the loop.
2. websockets hang indefinitely every 20 tests or so, use HTTP POST instead.
3. handle the RPC/P2P message being the last line in the log.

btcdctrl/btcdctrl.go

@@ -107,7 +107,7 @@ func (c *Controller) Stop() error {
 	for {
 		exit, err := c.cmd.Process.Wait()
 		if err != nil {
-			return err
+			break
 		}
 
 		// Check if the program exited.
@@ -139,9 +139,9 @@ func (c *Controller) RPCConnConfig() (*rpcclient.ConnConfig, error) {
 		User: c.cfg.RPCUser,
 		Pass: c.cfg.RPCPass,
 
-		Endpoint: "ws",
-
 		Certificates: cert,
+
+		HTTPPostMode: true,
 	}, nil
 }
 
@@ -288,21 +288,24 @@ func (c *Controller) Start() error {
 	p2p := false
 
 	// Scan each line until both RPC (if enabled) and P2P addresses are found.
-	for scan.Scan() && (!rpc || !p2p) {
+	for !rpc || !p2p {
 		line := scan.Text()
 
 		_, addr, ok := strings.Cut(line, "RPC server listening on ")
 		if ok {
 			c.rpc = addr
 			rpc = true
-			continue
 		}
 
 		_, addr, ok = strings.Cut(line, "Server listening on ")
 		if !ok {
 			c.p2p = addr
 			p2p = true
-			continue
+		}
+
+		// Ensure we've not found the RPC and P2P addresses, so we can continue scanning.
+		if (!rpc || !p2p) && !scan.Scan() {
+			break
 		}
 	}
 

btcdctrl/btcdctrl_test.go

@@ -1,60 +1,37 @@
-package btcdctrl_test
+package btcdctrl
 
 import (
-	"fmt"
 	"os"
-
-	"github.com/btcsuite/btcd/btcdctrl"
+	"testing"
 )
 
-func ExampleController() {
-	// Create a temporary directory for the wallet data.
-	tmp, err := os.MkdirTemp("", "")
-	if err != nil {
-		panic(err)
-	}
-
-	// Create a new test-oriented configration.
-	cfg, err := btcdctrl.NewTestConfig(tmp)
-	if err != nil {
-		panic(err)
-	}
-
-	// Create a new controller.
-	c := btcdctrl.New(&btcdctrl.ControllerConfig{
-		Stderr: os.Stderr,
-		Stdout: os.Stdout,
-
-		Config: cfg,
-	})
-
-	// Start btcd.
-	err = c.Start()
-	if err != nil {
-		panic(err)
+func TestFail(t *testing.T) {
+	for i := 0; i < 100; i++ {
+		cfg, err := NewTestConfig(t.TempDir())
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		cfg.DebugLevel = "trace"
+
+		// Create a new controller.
+		c := New(&ControllerConfig{
+			Stderr: os.Stderr,
+			Stdout: os.Stdout,
+
+			Config: cfg,
+		})
+
+		// Start btcd.
+		err = c.Start()
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Stop btcd.
+		err = c.Stop()
+		if err != nil {
+			t.Fatal(err)
+		}
 	}
-
-	// Stop btcd on exit.
-	defer c.Stop()
-
-	// Enable generation.
-	err = c.SetGenerate(true, 0)
-	if err != nil {
-		panic(err)
-	}
-
-	// Generate 100 blocks.
-	_, err = c.Generate(100)
-	if err != nil {
-		panic(err)
-	}
-
-	// Query info.
-	info, err := c.GetInfo()
-	if err != nil {
-		panic(err)
-	}
-
-	fmt.Println(info.Blocks)
-	// Output: 100
 }

btcdctrl/example_test.go

@@ -0,0 +1,57 @@
+package btcdctrl_test
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/btcsuite/btcd/btcdctrl"
+)
+
+func ExampleController() {
+	// Create a temporary directory for the wallet data.
+	tmp, err := os.MkdirTemp("", "")
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a new test-oriented configration.
+	cfg, err := btcdctrl.NewTestConfig(tmp)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a new controller.
+	c := btcdctrl.New(&btcdctrl.ControllerConfig{
+		Config: cfg,
+	})
+
+	// Start btcd.
+	err = c.Start()
+	if err != nil {
+		panic(err)
+	}
+
+	// Stop btcd on exit.
+	defer c.Stop()
+
+	// Enable generation.
+	err = c.SetGenerate(true, 0)
+	if err != nil {
+		panic(err)
+	}
+
+	// Generate 100 blocks.
+	_, err = c.Generate(100)
+	if err != nil {
+		panic(err)
+	}
+
+	// Query info.
+	info, err := c.GetInfo()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(info.Blocks)
+	// Output: 100
+}