| 1 | package main |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "fmt" |
| 6 | "net/http" |
| 7 | "net/http/httptest" |
| 8 | "net/url" |
| 9 | "strings" |
| 10 | "sync/atomic" |
| 11 | "testing" |
| 12 | "time" |
| 13 | ) |
| 14 | |
| 15 | // --- inbound limiter ------------------------------------------------------- |
| 16 | |
| 17 | func TestLimitInFlightRejectsOverflow(t *testing.T) { |
| 18 | entered := make(chan struct{}) |
| 19 | release := make(chan struct{}) |
| 20 | defer close(release) // unblock the parked handler when the test ends |
| 21 | h := limitInFlight(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 22 | entered <- struct{}{} |
| 23 | <-release |
| 24 | }), 1) |
| 25 | |
| 26 | // Occupy the single slot with a request parked inside the handler. |
| 27 | go h.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/", nil)) |
| 28 | <-entered |
| 29 | |
| 30 | // A second request must be shed immediately rather than queue. |
| 31 | rec := httptest.NewRecorder() |
| 32 | h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/", nil)) |
| 33 | if rec.Code != http.StatusServiceUnavailable { |
| 34 | t.Fatalf("overflow: want 503, got %d", rec.Code) |
| 35 | } |
| 36 | } |
| 37 | |
| 38 | func TestLimitInFlightStaticBypass(t *testing.T) { |
| 39 | // Capacity 0: no non-static request can ever get a slot. |
| 40 | h := limitInFlight(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 41 | w.WriteHeader(http.StatusOK) |
| 42 | }), 0) |
| 43 | |
| 44 | rec := httptest.NewRecorder() |
| 45 | h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/static/app.css", nil)) |
| 46 | if rec.Code != http.StatusOK { |
| 47 | t.Fatalf("static bypass: want 200, got %d", rec.Code) |
| 48 | } |
| 49 | |
| 50 | rec = httptest.NewRecorder() |
| 51 | h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/", nil)) |
| 52 | if rec.Code != http.StatusServiceUnavailable { |
| 53 | t.Fatalf("non-static: want 503, got %d", rec.Code) |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | // --- outbound fetch limiter ------------------------------------------------ |
| 58 | |
| 59 | func TestAcquireFetchRespectsContext(t *testing.T) { |
| 60 | saved := fetchSem |
| 61 | fetchSem = make(chan struct{}, 1) |
| 62 | defer func() { fetchSem = saved }() |
| 63 | |
| 64 | if err := acquireFetch(context.Background()); err != nil { |
| 65 | t.Fatalf("first acquire: %v", err) |
| 66 | } |
| 67 | // Slot is full; a cancelled context must bail instead of blocking forever. |
| 68 | ctx, cancel := context.WithCancel(context.Background()) |
| 69 | cancel() |
| 70 | if err := acquireFetch(ctx); err == nil { |
| 71 | t.Fatal("want error acquiring under cancelled ctx, got nil") |
| 72 | } |
| 73 | releaseFetch() |
| 74 | if err := acquireFetch(context.Background()); err != nil { |
| 75 | t.Fatalf("acquire after release: %v", err) |
| 76 | } |
| 77 | releaseFetch() |
| 78 | } |
| 79 | |
| 80 | // --- request parsing ------------------------------------------------------- |
| 81 | |
| 82 | func TestFeedURLsFromRequestCap(t *testing.T) { |
| 83 | parts := make([]string, 0, 30) |
| 84 | for i := 0; i < 30; i++ { |
| 85 | parts = append(parts, fmt.Sprintf("https://e%d.com/feed", i)) |
| 86 | } |
| 87 | q := url.QueryEscape(strings.Join(parts, ",")) |
| 88 | req := httptest.NewRequest(http.MethodGet, "/?url="+q, nil) |
| 89 | if got := len(feedURLsFromRequest(req)); got != maxFeedURLs { |
| 90 | t.Fatalf("cap: want %d urls, got %d", maxFeedURLs, got) |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | func TestFeedURLsFromRequestFallsBackToUrls(t *testing.T) { |
| 95 | req := httptest.NewRequest(http.MethodGet, "/?urls=https://a.com/feed,https://b.com/feed", nil) |
| 96 | if got := len(feedURLsFromRequest(req)); got != 2 { |
| 97 | t.Fatalf("urls param: want 2, got %d", got) |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | func TestOGCacheKeyOrderIndependent(t *testing.T) { |
| 102 | a := ogCacheKey([]string{"https://b.com", "https://a.com"}) |
| 103 | b := ogCacheKey([]string{"https://a.com", "https://b.com"}) |
| 104 | if a != b { |
| 105 | t.Fatalf("cache key not order-independent: %q vs %q", a, b) |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | // --- feed cache ------------------------------------------------------------ |
| 110 | |
| 111 | func TestFeedCacheEvictsLRU(t *testing.T) { |
| 112 | c := newFeedCache(time.Minute, 1) |
| 113 | c.store("a", &FetchResult{Title: "a"}) |
| 114 | c.store("b", &FetchResult{Title: "b"}) |
| 115 | if _, ok := c.lookup("a"); ok { |
| 116 | t.Fatal("a should have been evicted") |
| 117 | } |
| 118 | if _, ok := c.lookup("b"); !ok { |
| 119 | t.Fatal("b should still be cached") |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | func TestFeedCacheExpires(t *testing.T) { |
| 124 | c := newFeedCache(time.Millisecond, 8) |
| 125 | c.store("a", &FetchResult{Title: "a"}) |
| 126 | time.Sleep(5 * time.Millisecond) |
| 127 | if _, ok := c.lookup("a"); ok { |
| 128 | t.Fatal("entry should have expired") |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // --- image cache ----------------------------------------------------------- |
| 133 | |
| 134 | func TestImageCacheRendersOnce(t *testing.T) { |
| 135 | c := newImageCache(time.Minute, 4) |
| 136 | var calls int32 |
| 137 | render := func() ([]byte, error) { |
| 138 | atomic.AddInt32(&calls, 1) |
| 139 | return []byte("png"), nil |
| 140 | } |
| 141 | for i := 0; i < 3; i++ { |
| 142 | if _, err := c.getOrRender("k", render); err != nil { |
| 143 | t.Fatalf("getOrRender: %v", err) |
| 144 | } |
| 145 | } |
| 146 | if calls != 1 { |
| 147 | t.Fatalf("render calls: want 1, got %d", calls) |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | // --- fetchFeed ------------------------------------------------------------- |
| 152 | |
| 153 | const sampleRSS = `<?xml version="1.0"?> |
| 154 | <rss version="2.0"><channel> |
| 155 | <title>Example</title><link>https://example.com</link> |
| 156 | <item><title>Hello</title><link>https://example.com/hello</link></item> |
| 157 | </channel></rss>` |
| 158 | |
| 159 | func TestFetchFeedParses(t *testing.T) { |
| 160 | srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 161 | w.Header().Set("ETag", `"v1"`) |
| 162 | fmt.Fprint(w, sampleRSS) |
| 163 | })) |
| 164 | defer srv.Close() |
| 165 | |
| 166 | res, err := fetchFeed(context.Background(), srv.URL, "", "") |
| 167 | if err != nil { |
| 168 | t.Fatalf("fetchFeed: %v", err) |
| 169 | } |
| 170 | if res.Title != "Example" { |
| 171 | t.Fatalf("title: want Example, got %q", res.Title) |
| 172 | } |
| 173 | if len(res.Entries) != 1 || res.Entries[0].Link != "https://example.com/hello" { |
| 174 | t.Fatalf("entries: %+v", res.Entries) |
| 175 | } |
| 176 | if res.ETag != `"v1"` { |
| 177 | t.Fatalf("etag: want v1, got %q", res.ETag) |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | func TestFetchFeedNotModified(t *testing.T) { |
| 182 | srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 183 | if r.Header.Get("If-None-Match") == `"v1"` { |
| 184 | w.WriteHeader(http.StatusNotModified) |
| 185 | return |
| 186 | } |
| 187 | fmt.Fprint(w, sampleRSS) |
| 188 | })) |
| 189 | defer srv.Close() |
| 190 | |
| 191 | res, err := fetchFeed(context.Background(), srv.URL, `"v1"`, "") |
| 192 | if err != nil { |
| 193 | t.Fatalf("fetchFeed 304: %v", err) |
| 194 | } |
| 195 | if res.Status != http.StatusNotModified { |
| 196 | t.Fatalf("status: want 304, got %d", res.Status) |
| 197 | } |
| 198 | if res.ETag != `"v1"` { |
| 199 | t.Fatalf("etag carried forward: want v1, got %q", res.ETag) |
| 200 | } |
| 201 | } |