todo-hetzner/app/internal/handler/handler_test.go

package handler

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"todo-hetzner/app/internal/model"
)

type fakeStore struct {
	todos   []model.Todo
	created string
	toggled int64
	deleted int64
	pingErr error
}

func (s *fakeStore) List(context.Context) ([]model.Todo, error) { return s.todos, nil }
func (s *fakeStore) Create(_ context.Context, title string) error {
	s.created = title
	return nil
}
func (s *fakeStore) Toggle(_ context.Context, id int64) (bool, error) {
	s.toggled = id
	return id != 404, nil
}
func (s *fakeStore) Delete(_ context.Context, id int64) (bool, error) {
	s.deleted = id
	return id != 404, nil
}
func (s *fakeStore) Ping(context.Context) error { return s.pingErr }

func testHandler(t *testing.T, store *fakeStore) http.Handler {
	t.Helper()
	h, err := New(store, slog.New(slog.NewTextHandler(io.Discard, nil)))
	if err != nil {
		t.Fatal(err)
	}
	return h.Routes()
}

func TestListRendersEscapedTodos(t *testing.T) {
	router := testHandler(t, &fakeStore{todos: []model.Todo{{ID: 1, Title: "<script>alert(1)</script>"}}})
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
	if recorder.Code != http.StatusOK {
		t.Fatalf("status = %d", recorder.Code)
	}
	if strings.Contains(recorder.Body.String(), "<script>") || !strings.Contains(recorder.Body.String(), "&lt;script&gt;") {
		t.Fatalf("title was not escaped: %s", recorder.Body.String())
	}
	if got := recorder.Header().Get("Referrer-Policy"); got != "same-origin" {
		t.Fatalf("Referrer-Policy = %q, want %q", got, "same-origin")
	}
}

func TestCreateValidatesAndTrimsTitle(t *testing.T) {
	store := &fakeStore{}
	router := testHandler(t, store)
	form := url.Values{"title": {"  ship it  "}}
	req := httptest.NewRequest(http.MethodPost, "/todos", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, req)
	if recorder.Code != http.StatusSeeOther || store.created != "ship it" {
		t.Fatalf("status = %d, created = %q", recorder.Code, store.created)
	}

	req = httptest.NewRequest(http.MethodPost, "/todos", strings.NewReader("title=++"))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	recorder = httptest.NewRecorder()
	router.ServeHTTP(recorder, req)
	if recorder.Code != http.StatusUnprocessableEntity {
		t.Fatalf("empty title status = %d", recorder.Code)
	}
}

func TestMutationsAndNotFound(t *testing.T) {
	store := &fakeStore{}
	router := testHandler(t, store)
	for _, tc := range []struct {
		path string
		want int
	}{
		{"/todos/12/toggle", http.StatusSeeOther},
		{"/todos/13/delete", http.StatusSeeOther},
		{"/todos/404/delete", http.StatusNotFound},
		{"/todos/nope/toggle", http.StatusBadRequest},
	} {
		recorder := httptest.NewRecorder()
		router.ServeHTTP(recorder, httptest.NewRequest(http.MethodPost, tc.path, nil))
		if recorder.Code != tc.want {
			t.Errorf("%s status = %d, want %d", tc.path, recorder.Code, tc.want)
		}
	}
	if store.toggled != 12 || store.deleted != 404 {
		t.Fatalf("toggled = %d, deleted = %d", store.toggled, store.deleted)
	}
}

func TestHealth(t *testing.T) {
	store := &fakeStore{}
	router := testHandler(t, store)
	for _, tc := range []struct {
		err  error
		want int
	}{{nil, http.StatusOK}, {errors.New("down"), http.StatusServiceUnavailable}} {
		store.pingErr = tc.err
		recorder := httptest.NewRecorder()
		router.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/healthz", nil))
		if recorder.Code != tc.want {
			t.Errorf("status = %d, want %d", recorder.Code, tc.want)
		}
	}
}

func TestRejectsCrossOriginMutation(t *testing.T) {
	router := testHandler(t, &fakeStore{})
	req := httptest.NewRequest(http.MethodPost, "/todos/1/delete", nil)
	req.Header.Set("Origin", "https://attacker.example")
	recorder := httptest.NewRecorder()
	router.ServeHTTP(recorder, req)
	if recorder.Code != http.StatusForbidden {
		t.Fatalf("status = %d", recorder.Code)
	}
}