integration: allow specifying connection behavior

integration/rpctest/rpc_harness.go

@@ -34,6 +34,14 @@ const (
 	// BlockVersion is the default block version used when generating
 	// blocks.
 	BlockVersion = 4
+
+	// DefaultMaxConnectionRetries is the default number of times we re-try
+	// to connect to the node after starting it.
+	DefaultMaxConnectionRetries = 20
+
+	// DefaultConnectionRetryTimeout is the default duration we wait between
+	// two connection attempts.
+	DefaultConnectionRetryTimeout = 50 * time.Millisecond
 )
 
 var (
@@ -85,15 +93,22 @@ type Harness struct {
 	// to.
 	ActiveNet *chaincfg.Params
 
+	// MaxConnRetries is the maximum number of times we re-try to connect to
+	// the node after starting it.
+	MaxConnRetries int
+
+	// ConnectionRetryTimeout is the duration we wait between two connection
+	// attempts.
+	ConnectionRetryTimeout time.Duration
+
 	Node     *rpcclient.Client
 	node     *node
 	handlers *rpcclient.NotificationHandlers
 
 	wallet *memWallet
 
-	testNodeDir    string
-	maxConnRetries int
-	nodeNum        int
+	testNodeDir string
+	nodeNum     int
 
 	sync.Mutex
 }
@@ -200,13 +215,14 @@ func New(activeNet *chaincfg.Params, handlers *rpcclient.NotificationHandlers,
 	}
 
 	h := &Harness{
-		handlers:       handlers,
-		node:           node,
-		maxConnRetries: 20,
-		testNodeDir:    nodeTestData,
-		ActiveNet:      activeNet,
-		nodeNum:        nodeNum,
-		wallet:         wallet,
+		handlers:               handlers,
+		node:                   node,
+		MaxConnRetries:         DefaultMaxConnectionRetries,
+		ConnectionRetryTimeout: DefaultConnectionRetryTimeout,
+		testNodeDir:            nodeTestData,
+		ActiveNet:              activeNet,
+		nodeNum:                nodeNum,
+		wallet:                 wallet,
 	}
 
 	// Track this newly created test instance within the package level
@@ -322,9 +338,9 @@ func (h *Harness) connectRPCClient() error {
 	var err error
 
 	rpcConf := h.node.config.rpcConnConfig()
-	for i := 0; i < h.maxConnRetries; i++ {
+	for i := 0; i < h.MaxConnRetries; i++ {
 		if client, err = rpcclient.New(&rpcConf, h.handlers); err != nil {
-			time.Sleep(time.Duration(i) * 50 * time.Millisecond)
+			time.Sleep(time.Duration(i) * h.ConnectionRetryTimeout)
 			continue
 		}
 		break