feat: add celeristest.WithHandlers for middleware chain testing

celeristest/celeristest.go

@@ -83,6 +83,7 @@ type config struct {
 	params     [][2]string
 	cookies    [][2]string
 	remoteAddr string
+	handlers   []any
 }
 
 // WithBody sets the request body.
@@ -128,6 +129,18 @@ func WithRemoteAddr(addr string) Option {
 	return func(c *config) { c.remoteAddr = addr }
 }
 
+// WithHandlers sets the handler chain on the test context. This enables
+// middleware chain testing where mw1 calls c.Next() → mw2 runs → ... → final handler.
+// Pass celeris.HandlerFunc values; they are stored as []any to avoid import cycles.
+func WithHandlers(handlers ...celeris.HandlerFunc) Option {
+	return func(c *config) {
+		c.handlers = make([]any, len(handlers))
+		for i, h := range handlers {
+			c.handlers[i] = h
+		}
+	}
+}
+
 // ReleaseContext returns a [celeris.Context] to the pool. The context must not
 // be used after this call.
 func ReleaseContext(ctx *celeris.Context) {
@@ -191,5 +204,8 @@ func NewContext(method, path string, opts ...Option) (*celeris.Context, *Respons
 	for _, p := range cfg.params {
 		ctxkit.AddParam(ctx, p[0], p[1])
 	}
+	if len(cfg.handlers) > 0 {
+		ctxkit.SetHandlers(ctx, cfg.handlers)
+	}
 	return ctx, rec
 }

context.go

@@ -23,6 +23,15 @@ func init() {
 		ctx := c.(*Context)
 		ctx.params = append(ctx.params, Param{Key: key, Value: value})
 	}
+	ctxkit.SetHandlers = func(c any, handlers []any) {
+		ctx := c.(*Context)
+		chain := make([]HandlerFunc, len(handlers))
+		for i, h := range handlers {
+			chain[i] = h.(HandlerFunc)
+		}
+		ctx.handlers = chain
+		ctx.index = -1
+	}
 }
 
 // Context is the request context passed to handlers. It is pooled via sync.Pool.

internal/ctxkit/ctxkit.go

@@ -10,4 +10,5 @@ var (
 	NewContext     func(s *stream.Stream) any
 	ReleaseContext func(c any)
 	AddParam       func(c any, key, value string)
+	SetHandlers    func(c any, handlers []any)
 )