Add production features: slog adapter, scan helpers, slow query logging, pool stats, tracer passthrough, test tx isolation

- slog.go: SlogLogger adapts *slog.Logger to dbx.Logger interface
- scan.go: Collect[T] and CollectOne[T] generic helpers using pgx.RowToStructByName
- cluster.go: slow query logging via Config.SlowQueryThreshold (Warn level in queryEnd)
- stats.go: PoolStats with Cluster.Stats() aggregating pool stats across all nodes
- config.go/node.go: NodeConfig.Tracer passthrough for pgx.QueryTracer (OpenTelemetry)
- options.go: WithSlowQueryThreshold and WithTracer functional options
- dbxtest/tx.go: RunInTx runs callback in always-rolled-back transaction for test isolation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.cursorrules

@@ -23,8 +23,11 @@ You are working on `git.codelab.vc/pkg/dbx`, a Go PostgreSQL cluster library bui
   - `tx.go` — RunTx, RunTxOptions, InjectQuerier, ExtractQuerier
   - `errors.go` — IsRetryable, IsConnectionError, IsConstraintViolation, PgErrorCode
   - `config.go` — Config, NodeConfig, PoolConfig, RetryConfig, HealthCheckConfig
-  - `options.go` — functional options (WithLogger, WithMetrics, WithRetry, WithHealthCheck)
-- `dbxtest/` — test helpers: NewTestCluster, TestLogger
+  - `options.go` — functional options (WithLogger, WithMetrics, WithRetry, WithHealthCheck, WithSlowQueryThreshold, WithTracer)
+  - `slog.go` — SlogLogger adapting *slog.Logger to dbx.Logger
+  - `scan.go` — Collect[T], CollectOne[T] generic row scan helpers
+  - `stats.go` — PoolStats aggregate pool statistics via Cluster.Stats()
+- `dbxtest/` — test helpers: NewTestCluster, TestLogger, RunInTx
 
 ## Code conventions
 

AGENTS.md

@@ -11,17 +11,21 @@ Universal guide for AI coding agents working with this codebase.
 ```
 dbx/                      Root — Cluster, Node, Balancer, retry, health, errors, tx, config
 ├── dbx.go                Interfaces: Querier, DB, Logger, MetricsHook
-├── cluster.go            Cluster — routing, write/read operations
-├── node.go               Node — pgxpool.Pool wrapper with health state
+├── cluster.go            Cluster — routing, write/read operations, slow query logging
+├── node.go               Node — pgxpool.Pool wrapper with health state, tracer passthrough
 ├── balancer.go           Balancer interface + RoundRobinBalancer
 ├── retry.go              retrier — exponential backoff with jitter and node fallback
 ├── health.go             healthChecker — background goroutine pinging nodes
 ├── tx.go                 RunTx, RunTxOptions, InjectQuerier, ExtractQuerier
 ├── errors.go             Error classification (IsRetryable, IsConnectionError, etc.)
 ├── config.go             Config, NodeConfig, PoolConfig, RetryConfig, HealthCheckConfig
-├── options.go            Functional options (WithLogger, WithMetrics, WithRetry, etc.)
+├── options.go            Functional options (WithLogger, WithMetrics, WithRetry, WithTracer, etc.)
+├── slog.go               SlogLogger — adapts *slog.Logger to dbx.Logger
+├── scan.go               Collect[T], CollectOne[T] — generic row scan helpers
+├── stats.go              PoolStats — aggregate pool statistics via Cluster.Stats()
 └── dbxtest/
-    └── dbxtest.go        Test helpers: NewTestCluster, TestLogger
+    ├── dbxtest.go        Test helpers: NewTestCluster, TestLogger
+    └── tx.go             RunInTx — test transaction isolation (always rolled back)
 ```
 
 ## Routing architecture

CLAUDE.md

@@ -24,6 +24,12 @@ go vet ./...                            # static analysis
 - **Health checker** — background goroutine pings all nodes on an interval, flips `Node.healthy` atomic bool
 - **RunTx** — panic-safe transaction wrapper: recovers panics, rolls back, re-panics
 - **Querier injection** — `InjectQuerier`/`ExtractQuerier` pass `Querier` via context for service layers
+- **SlogLogger** — adapts `*slog.Logger` to the `dbx.Logger` interface (`slog.go`)
+- **Collect/CollectOne** — generic scan helpers using `pgx.RowToStructByName` (`scan.go`)
+- **Slow query logging** — `Config.SlowQueryThreshold` triggers Warn-level logging in `queryEnd`
+- **PoolStats** — `Cluster.Stats()` aggregates pool statistics across all nodes (`stats.go`)
+- **Tracer passthrough** — `NodeConfig.Tracer` / `WithTracer` sets `pgx.QueryTracer` for OpenTelemetry
+- **RunInTx** — test helper that runs a callback in an always-rolled-back transaction (`dbxtest/tx.go`)
 
 ### Error classification
 
@@ -40,6 +46,7 @@ go vet ./...                            # static analysis
 - `atomic.Bool` for thread safety (`Node.healthy`, `Cluster.closed`)
 - `dbxtest.NewTestCluster` skips tests when DB unreachable, auto-closes via `t.Cleanup`
 - `dbxtest.TestLogger` writes to `testing.T` for test log output
+- `dbxtest.RunInTx` runs a callback in a transaction that is always rolled back
 
 ## See also
 

README.md

@@ -50,6 +50,9 @@ cluster.RunTx(ctx, func(ctx context.Context, tx pgx.Tx) error {
 | `healthChecker` | Background goroutine that pings all nodes on an interval. |
 | `Querier` injection | `InjectQuerier` / `ExtractQuerier` — context-based Querier for service layers. |
 | `MetricsHook` | Optional callbacks: query start/end, retry, node up/down, replica fallback. |
+| `SlogLogger` | Adapts `*slog.Logger` to the `dbx.Logger` interface. |
+| `Collect`/`CollectOne` | Generic scan helpers — read rows directly into structs via `pgx.RowToStructByName`. |
+| `PoolStats` | Aggregate pool statistics across all nodes via `cluster.Stats()`. |
 
 ## Routing
 
@@ -159,6 +162,60 @@ dbx.PgErrorCode(err)          // extract raw PG error code
 
 Sentinel errors: `ErrNoHealthyNode`, `ErrClusterClosed`, `ErrRetryExhausted`.
 
+## slog integration
+
+```go
+cluster, _ := dbx.NewCluster(ctx, dbx.Config{
+    Master: dbx.NodeConfig{DSN: "postgres://..."},
+    Logger: dbx.NewSlogLogger(slog.Default()),
+})
+```
+
+## Scan helpers
+
+Generic functions that eliminate row scanning boilerplate:
+
+```go
+type User struct {
+    ID   int    `db:"id"`
+    Name string `db:"name"`
+}
+
+users, err := dbx.Collect[User](ctx, cluster, "SELECT id, name FROM users WHERE active = $1", true)
+
+user, err := dbx.CollectOne[User](ctx, cluster, "SELECT id, name FROM users WHERE id = $1", 42)
+// returns pgx.ErrNoRows if not found
+```
+
+## Slow query logging
+
+```go
+cluster, _ := dbx.NewCluster(ctx, dbx.Config{
+    Master:             dbx.NodeConfig{DSN: "postgres://..."},
+    Logger:             dbx.NewSlogLogger(slog.Default()),
+    SlowQueryThreshold: 100 * time.Millisecond,
+})
+// queries exceeding threshold are logged at Warn level
+```
+
+## Pool stats
+
+```go
+stats := cluster.Stats()
+fmt.Println(stats.TotalConns, stats.IdleConns, stats.AcquireCount)
+// per-node stats: stats.Nodes["master"], stats.Nodes["replica-1"]
+```
+
+## OpenTelemetry / pgx tracer
+
+Pass any `pgx.QueryTracer` (e.g., `otelpgx.NewTracer()`) to instrument all queries:
+
+```go
+dbx.ApplyOptions(&cfg, dbx.WithTracer(otelpgx.NewTracer()))
+```
+
+Or set per-node via `NodeConfig.Tracer`.
+
 ## dbxtest helpers
 
 The `dbxtest` package provides test helpers:
@@ -171,6 +228,18 @@ func TestMyRepo(t *testing.T) {
 }
 ```
 
+### Transaction isolation for tests
+
+```go
+func TestCreateUser(t *testing.T) {
+    c := dbxtest.NewTestCluster(t)
+    dbxtest.RunInTx(t, c, func(ctx context.Context, q dbx.Querier) {
+        // all changes are rolled back after fn returns
+        _, _ = q.Exec(ctx, "INSERT INTO users (name) VALUES ($1)", "test")
+    })
+}
+```
+
 Set `DBX_TEST_DSN` env var to override the default DSN (`postgres://postgres:postgres@localhost:5432/dbx_test?sslmode=disable`).
 
 ## Requirements

cluster.go

@@ -17,12 +17,13 @@ type Cluster struct {
 	replicas []*Node
 	all      []*Node // master + replicas for health checker
 
-	balancer Balancer
-	retrier  *retrier
-	health   *healthChecker
-	logger   Logger
-	metrics  *MetricsHook
-	closed   atomic.Bool
+	balancer           Balancer
+	retrier            *retrier
+	health             *healthChecker
+	logger             Logger
+	metrics            *MetricsHook
+	slowQueryThreshold time.Duration
+	closed             atomic.Bool
 }
 
 // NewCluster creates a Cluster, connecting to all configured nodes.
@@ -53,13 +54,14 @@ func NewCluster(ctx context.Context, cfg Config) (*Cluster, error) {
 	all = append(all, replicas...)
 
 	c := &Cluster{
-		master:   master,
-		replicas: replicas,
-		all:      all,
-		balancer: NewRoundRobinBalancer(),
-		retrier:  newRetrier(cfg.Retry, cfg.Logger, cfg.Metrics),
-		logger:   cfg.Logger,
-		metrics:  cfg.Metrics,
+		master:             master,
+		replicas:           replicas,
+		all:                all,
+		balancer:           NewRoundRobinBalancer(),
+		retrier:            newRetrier(cfg.Retry, cfg.Logger, cfg.Metrics),
+		logger:             cfg.Logger,
+		metrics:            cfg.Metrics,
+		slowQueryThreshold: cfg.SlowQueryThreshold,
 	}
 
 	c.health = newHealthChecker(all, cfg.HealthCheck, cfg.Logger, cfg.Metrics)
@@ -232,6 +234,13 @@ func (c *Cluster) queryEnd(ctx context.Context, node, sql string, err error, d t
 	if c.metrics != nil && c.metrics.OnQueryEnd != nil {
 		c.metrics.OnQueryEnd(ctx, node, sql, err, d)
 	}
+	if c.slowQueryThreshold > 0 && d >= c.slowQueryThreshold {
+		c.logger.Warn(ctx, "dbx: slow query",
+			"node", node,
+			"duration", d,
+			"sql", sql,
+		)
+	}
 }
 
 // errRow implements pgx.Row for error cases.

config.go

@@ -1,22 +1,28 @@
 package dbx
 
-import "time"
+import (
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
 
 // Config is the top-level configuration for a Cluster.
 type Config struct {
-	Master      NodeConfig
-	Replicas    []NodeConfig
-	Retry       RetryConfig
-	Logger      Logger
-	Metrics     *MetricsHook
-	HealthCheck HealthCheckConfig
+	Master             NodeConfig
+	Replicas           []NodeConfig
+	Retry              RetryConfig
+	Logger             Logger
+	Metrics            *MetricsHook
+	HealthCheck        HealthCheckConfig
+	SlowQueryThreshold time.Duration
 }
 
 // NodeConfig describes a single database node.
 type NodeConfig struct {
-	Name string // human-readable name for logs/metrics, e.g. "master", "replica-1"
-	DSN  string
-	Pool PoolConfig
+	Name   string // human-readable name for logs/metrics, e.g. "master", "replica-1"
+	DSN    string
+	Pool   PoolConfig
+	Tracer pgx.QueryTracer
 }
 
 // PoolConfig controls pgxpool.Pool parameters.

dbxtest/tx.go

@@ -0,0 +1,27 @@
+package dbxtest
+
+import (
+	"context"
+	"testing"
+
+	"git.codelab.vc/pkg/dbx"
+)
+
+// RunInTx executes fn inside a transaction that is always rolled back.
+// This is useful for tests that modify data but should not leave side effects.
+// The callback receives a dbx.Querier (not pgx.Tx) so it is compatible with
+// InjectQuerier/ExtractQuerier patterns.
+func RunInTx(t testing.TB, c *dbx.Cluster, fn func(ctx context.Context, q dbx.Querier)) {
+	t.Helper()
+
+	ctx := context.Background()
+	tx, err := c.Begin(ctx)
+	if err != nil {
+		t.Fatalf("dbxtest.RunInTx: begin: %v", err)
+	}
+	defer func() {
+		_ = tx.Rollback(ctx)
+	}()
+
+	fn(ctx, tx)
+}

dbxtest/tx_test.go

@@ -0,0 +1,50 @@
+package dbxtest_test
+
+import (
+	"context"
+	"testing"
+
+	"git.codelab.vc/pkg/dbx"
+	"git.codelab.vc/pkg/dbx/dbxtest"
+)
+
+func TestRunInTx(t *testing.T) {
+	c := dbxtest.NewTestCluster(t)
+	ctx := context.Background()
+
+	// Create a table that persists across the test.
+	_, err := c.Exec(ctx, `CREATE TABLE IF NOT EXISTS test_run_in_tx (id int)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		_, _ = c.Exec(context.Background(), `DROP TABLE IF EXISTS test_run_in_tx`)
+	})
+
+	dbxtest.RunInTx(t, c, func(ctx context.Context, q dbx.Querier) {
+		_, err := q.Exec(ctx, `INSERT INTO test_run_in_tx (id) VALUES (1)`)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Row should be visible within the transaction.
+		var count int
+		err = q.QueryRow(ctx, `SELECT count(*) FROM test_run_in_tx`).Scan(&count)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if count != 1 {
+			t.Fatalf("expected 1 row in tx, got %d", count)
+		}
+	})
+
+	// After RunInTx returns, the transaction was rolled back; row should not exist.
+	var count int
+	err = c.QueryRow(ctx, `SELECT count(*) FROM test_run_in_tx`).Scan(&count)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if count != 0 {
+		t.Errorf("expected 0 rows after rollback, got %d", count)
+	}
+}

node.go

@@ -33,6 +33,9 @@ func connectNode(ctx context.Context, cfg NodeConfig) (*Node, error) {
 		return nil, err
 	}
 	applyPoolConfig(poolCfg, cfg.Pool)
+	if cfg.Tracer != nil {
+		poolCfg.ConnConfig.Tracer = cfg.Tracer
+	}
 
 	pool, err := pgxpool.NewWithConfig(ctx, poolCfg)
 	if err != nil {

options.go

@@ -1,5 +1,11 @@
 package dbx
 
+import (
+	"time"
+
+	"github.com/jackc/pgx/v5"
+)
+
 // Option is a functional option for NewCluster.
 type Option func(*Config)
 
@@ -31,6 +37,25 @@ func WithHealthCheck(h HealthCheckConfig) Option {
 	}
 }
 
+// WithSlowQueryThreshold sets the threshold for slow query warnings.
+// Queries taking longer than d will be logged at Warn level.
+func WithSlowQueryThreshold(d time.Duration) Option {
+	return func(c *Config) {
+		c.SlowQueryThreshold = d
+	}
+}
+
+// WithTracer sets the pgx.QueryTracer on master and all replica configs.
+// This enables OpenTelemetry integration via libraries like otelpgx.
+func WithTracer(t pgx.QueryTracer) Option {
+	return func(c *Config) {
+		c.Master.Tracer = t
+		for i := range c.Replicas {
+			c.Replicas[i].Tracer = t
+		}
+	}
+}
+
 // ApplyOptions applies functional options to a Config.
 func ApplyOptions(cfg *Config, opts ...Option) {
 	for _, o := range opts {

scan.go

@@ -0,0 +1,28 @@
+package dbx
+
+import (
+	"context"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// Collect executes a read query and collects all rows into a slice of T
+// using pgx.RowToStructByName. T must be a struct with db tags matching column names.
+func Collect[T any](ctx context.Context, c *Cluster, sql string, args ...any) ([]T, error) {
+	rows, err := c.ReadQuery(ctx, sql, args...)
+	if err != nil {
+		return nil, err
+	}
+	return pgx.CollectRows(rows, pgx.RowToStructByName[T])
+}
+
+// CollectOne executes a read query and collects exactly one row into T.
+// Returns pgx.ErrNoRows if no rows are returned.
+func CollectOne[T any](ctx context.Context, c *Cluster, sql string, args ...any) (T, error) {
+	rows, err := c.ReadQuery(ctx, sql, args...)
+	if err != nil {
+		var zero T
+		return zero, err
+	}
+	return pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[T])
+}

scan_test.go

@@ -0,0 +1,81 @@
+package dbx_test
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"git.codelab.vc/pkg/dbx"
+	"git.codelab.vc/pkg/dbx/dbxtest"
+	"github.com/jackc/pgx/v5"
+)
+
+type scanRow struct {
+	ID   int    `db:"id"`
+	Name string `db:"name"`
+}
+
+func TestCollect(t *testing.T) {
+	c := dbxtest.NewTestCluster(t)
+	ctx := context.Background()
+
+	_, err := c.Exec(ctx, `CREATE TEMPORARY TABLE test_collect (id int, name text)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = c.Exec(ctx, `INSERT INTO test_collect (id, name) VALUES (1, 'alice'), (2, 'bob')`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rows, err := dbx.Collect[scanRow](ctx, c, `SELECT id, name FROM test_collect ORDER BY id`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rows) != 2 {
+		t.Fatalf("expected 2 rows, got %d", len(rows))
+	}
+	if rows[0].ID != 1 || rows[0].Name != "alice" {
+		t.Errorf("row 0: got %+v", rows[0])
+	}
+	if rows[1].ID != 2 || rows[1].Name != "bob" {
+		t.Errorf("row 1: got %+v", rows[1])
+	}
+}
+
+func TestCollectOne(t *testing.T) {
+	c := dbxtest.NewTestCluster(t)
+	ctx := context.Background()
+
+	_, err := c.Exec(ctx, `CREATE TEMPORARY TABLE test_collect_one (id int, name text)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = c.Exec(ctx, `INSERT INTO test_collect_one (id, name) VALUES (1, 'alice')`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	row, err := dbx.CollectOne[scanRow](ctx, c, `SELECT id, name FROM test_collect_one WHERE id = 1`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if row.ID != 1 || row.Name != "alice" {
+		t.Errorf("got %+v", row)
+	}
+}
+
+func TestCollectOneNoRows(t *testing.T) {
+	c := dbxtest.NewTestCluster(t)
+	ctx := context.Background()
+
+	_, err := c.Exec(ctx, `CREATE TEMPORARY TABLE test_collect_norows (id int, name text)`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = dbx.CollectOne[scanRow](ctx, c, `SELECT id, name FROM test_collect_norows`)
+	if !errors.Is(err, pgx.ErrNoRows) {
+		t.Errorf("expected pgx.ErrNoRows, got %v", err)
+	}
+}

slog.go

@@ -0,0 +1,38 @@
+package dbx
+
+import (
+	"context"
+	"log/slog"
+)
+
+// SlogLogger adapts *slog.Logger to the dbx.Logger interface.
+type SlogLogger struct {
+	Logger *slog.Logger
+}
+
+// NewSlogLogger creates a SlogLogger. If l is nil, slog.Default() is used.
+func NewSlogLogger(l *slog.Logger) *SlogLogger {
+	if l == nil {
+		l = slog.Default()
+	}
+	return &SlogLogger{Logger: l}
+}
+
+func (s *SlogLogger) Debug(ctx context.Context, msg string, fields ...any) {
+	s.Logger.DebugContext(ctx, msg, fields...)
+}
+
+func (s *SlogLogger) Info(ctx context.Context, msg string, fields ...any) {
+	s.Logger.InfoContext(ctx, msg, fields...)
+}
+
+func (s *SlogLogger) Warn(ctx context.Context, msg string, fields ...any) {
+	s.Logger.WarnContext(ctx, msg, fields...)
+}
+
+func (s *SlogLogger) Error(ctx context.Context, msg string, fields ...any) {
+	s.Logger.ErrorContext(ctx, msg, fields...)
+}
+
+// Compile-time check.
+var _ Logger = (*SlogLogger)(nil)

slog_test.go

@@ -0,0 +1,52 @@
+package dbx
+
+import (
+	"bytes"
+	"context"
+	"log/slog"
+	"strings"
+	"testing"
+)
+
+func TestSlogLogger(t *testing.T) {
+	var buf bytes.Buffer
+	h := slog.NewTextHandler(&buf, &slog.HandlerOptions{Level: slog.LevelDebug})
+	l := NewSlogLogger(slog.New(h))
+
+	ctx := context.Background()
+
+	l.Debug(ctx, "debug msg", "key", "val1")
+	l.Info(ctx, "info msg", "key", "val2")
+	l.Warn(ctx, "warn msg", "key", "val3")
+	l.Error(ctx, "error msg", "key", "val4")
+
+	out := buf.String()
+
+	for _, want := range []string{
+		"level=DEBUG",
+		"debug msg",
+		"key=val1",
+		"level=INFO",
+		"info msg",
+		"key=val2",
+		"level=WARN",
+		"warn msg",
+		"key=val3",
+		"level=ERROR",
+		"error msg",
+		"key=val4",
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("output missing %q\ngot: %s", want, out)
+		}
+	}
+}
+
+func TestNewSlogLoggerNil(t *testing.T) {
+	l := NewSlogLogger(nil)
+	if l.Logger == nil {
+		t.Fatal("expected non-nil logger when passing nil")
+	}
+	// should not panic
+	l.Info(context.Background(), "test")
+}

stats.go

@@ -0,0 +1,42 @@
+package dbx
+
+import (
+	"time"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// PoolStats is an aggregate of pool statistics across all nodes.
+type PoolStats struct {
+	AcquireCount         int64
+	AcquireDuration      time.Duration
+	AcquiredConns        int32
+	CanceledAcquireCount int64
+	ConstructingConns    int32
+	EmptyAcquireCount    int64
+	IdleConns            int32
+	MaxConns             int32
+	TotalConns           int32
+	Nodes                map[string]*pgxpool.Stat
+}
+
+// Stats returns aggregate pool statistics for all nodes in the cluster.
+func (c *Cluster) Stats() PoolStats {
+	ps := PoolStats{
+		Nodes: make(map[string]*pgxpool.Stat, len(c.all)),
+	}
+	for _, n := range c.all {
+		s := n.pool.Stat()
+		ps.Nodes[n.name] = s
+		ps.AcquireCount += s.AcquireCount()
+		ps.AcquireDuration += s.AcquireDuration()
+		ps.AcquiredConns += s.AcquiredConns()
+		ps.CanceledAcquireCount += s.CanceledAcquireCount()
+		ps.ConstructingConns += s.ConstructingConns()
+		ps.EmptyAcquireCount += s.EmptyAcquireCount()
+		ps.IdleConns += s.IdleConns()
+		ps.MaxConns += s.MaxConns()
+		ps.TotalConns += s.TotalConns()
+	}
+	return ps
+}

stats_test.go

@@ -0,0 +1,22 @@
+package dbx_test
+
+import (
+	"testing"
+
+	"git.codelab.vc/pkg/dbx/dbxtest"
+)
+
+func TestStats(t *testing.T) {
+	c := dbxtest.NewTestCluster(t)
+
+	ps := c.Stats()
+	if ps.Nodes == nil {
+		t.Fatal("Nodes map is nil")
+	}
+	if _, ok := ps.Nodes["test-master"]; !ok {
+		t.Error("expected test-master in Nodes")
+	}
+	if ps.MaxConns <= 0 {
+		t.Errorf("expected MaxConns > 0, got %d", ps.MaxConns)
+	}
+}