feat: add Recovery middleware for panic handling with verbose logging

backend/internal/api/middleware/recovery_test.go

@@ -0,0 +1,70 @@
+package middleware
+
+import (
+    "bytes"
+    "log"
+    "net/http"
+    "net/http/httptest"
+    "strings"
+    "testing"
+
+    "github.com/gin-gonic/gin"
+)
+
+func TestRecoveryLogsStacktraceVerbose(t *testing.T) {
+    old := log.Writer()
+    buf := &bytes.Buffer{}
+    log.SetOutput(buf)
+    defer log.SetOutput(old)
+
+    router := gin.New()
+    router.Use(Recovery(true))
+    router.GET("/panic", func(c *gin.Context) {
+        panic("test panic")
+    })
+
+    req := httptest.NewRequest(http.MethodGet, "/panic", nil)
+    w := httptest.NewRecorder()
+    router.ServeHTTP(w, req)
+
+    if w.Code != http.StatusInternalServerError {
+        t.Fatalf("expected status 500, got %d", w.Code)
+    }
+
+    out := buf.String()
+    if !strings.Contains(out, "PANIC: test panic") {
+        t.Fatalf("log did not include panic message: %s", out)
+    }
+    if !strings.Contains(out, "Stacktrace:") {
+        t.Fatalf("verbose log did not include stack trace: %s", out)
+    }
+}
+
+func TestRecoveryLogsBriefWhenNotVerbose(t *testing.T) {
+    old := log.Writer()
+    buf := &bytes.Buffer{}
+    log.SetOutput(buf)
+    defer log.SetOutput(old)
+
+    router := gin.New()
+    router.Use(Recovery(false))
+    router.GET("/panic", func(c *gin.Context) {
+        panic("brief panic")
+    })
+
+    req := httptest.NewRequest(http.MethodGet, "/panic", nil)
+    w := httptest.NewRecorder()
+    router.ServeHTTP(w, req)
+
+    if w.Code != http.StatusInternalServerError {
+        t.Fatalf("expected status 500, got %d", w.Code)
+    }
+
+    out := buf.String()
+    if !strings.Contains(out, "PANIC: brief panic") {
+        t.Fatalf("log did not include panic message: %s", out)
+    }
+    if strings.Contains(out, "Stacktrace:") {
+        t.Fatalf("non-verbose log unexpectedly included stacktrace: %s", out)
+    }
+}