fix: cut redirect and allow-path routing overhead

Reuse fixed-path and Allow-header buffers so redirect and OPTIONS handling stop rebuilding temporary data on every request. Cache fallback chains and add regression coverage for redirect, 404, 405, and Allow behavior to keep the faster miss paths stable.

engine_test.go

@@ -0,0 +1,102 @@
+package touka
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestHandleRequestRedirectFixedPath(t *testing.T) {
+	engine := New()
+	engine.GET("/api/v1/users/:id/settings", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodGet, "/API/V1/USERS/123/SETTINGS", nil, nil)
+	if rr.Code != http.StatusMovedPermanently {
+		t.Fatalf("expected fixed-path redirect status %d, got %d", http.StatusMovedPermanently, rr.Code)
+	}
+	if location := rr.Header().Get("Location"); location != "/api/v1/users/123/settings" {
+		t.Fatalf("expected fixed-path redirect location %q, got %q", "/api/v1/users/123/settings", location)
+	}
+}
+
+func TestHandleRequestSkipsFixedPathLookupForLowercaseMiss(t *testing.T) {
+	engine := New()
+	engine.GET("/api/v1/users/:id/settings", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodGet, "/does/not/exist", nil, nil)
+	if rr.Code != http.StatusNotFound {
+		t.Fatalf("expected lowercase miss to stay as 404, got %d", rr.Code)
+	}
+}
+
+func TestHandleRequestKeepsFixedPathLookupForUppercaseMiss(t *testing.T) {
+	engine := New()
+	engine.GET("/Users/Profile", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodGet, "/users/profile", nil, nil)
+	if rr.Code != http.StatusMovedPermanently {
+		t.Fatalf("expected uppercase route miss to trigger fixed-path redirect, got %d", rr.Code)
+	}
+	if location := rr.Header().Get("Location"); location != "/Users/Profile" {
+		t.Fatalf("expected uppercase route redirect location %q, got %q", "/Users/Profile", location)
+	}
+}
+
+func TestNoRouteCanContinueToDefaultNotFound(t *testing.T) {
+	engine := New()
+	engine.NoRoute(func(c *Context) {
+		c.Writer.Header().Set("X-NoRoute", "hit")
+		c.Next()
+	})
+
+	rr := PerformRequest(engine, http.MethodGet, "/missing", nil, nil)
+	if rr.Code != http.StatusNotFound {
+		t.Fatalf("expected default not found status %d, got %d", http.StatusNotFound, rr.Code)
+	}
+	if got := rr.Header().Get("X-NoRoute"); got != "hit" {
+		t.Fatalf("expected NoRoute middleware header to be preserved, got %q", got)
+	}
+}
+
+func TestMethodNotAllowedDoesNotContinueToNoRoute(t *testing.T) {
+	engine := New()
+	engine.GET("/users", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+	engine.NoRoute(func(c *Context) {
+		c.Writer.Header().Set("X-NoRoute", "hit")
+		c.Next()
+	})
+
+	rr := PerformRequest(engine, http.MethodDelete, "/users", nil, nil)
+	if rr.Code != http.StatusMethodNotAllowed {
+		t.Fatalf("expected method not allowed status %d, got %d", http.StatusMethodNotAllowed, rr.Code)
+	}
+	if got := rr.Header().Get("X-NoRoute"); got != "" {
+		t.Fatalf("expected NoRoute chain to be skipped after 405, got header %q", got)
+	}
+}
+
+func TestOptionsAllowHeaderListsMatchingMethods(t *testing.T) {
+	engine := New()
+	engine.GET("/users", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+	engine.POST("/users", func(c *Context) {
+		c.Status(http.StatusNoContent)
+	})
+
+	rr := PerformRequest(engine, http.MethodOptions, "/users", nil, nil)
+	if rr.Code != http.StatusOK {
+		t.Fatalf("expected OPTIONS allow status %d, got %d", http.StatusOK, rr.Code)
+	}
+	allow := rr.Header().Get("Allow")
+	if allow != "GET, POST" && allow != "POST, GET" {
+		t.Fatalf("expected Allow header to list matching methods, got %q", allow)
+	}
+}