| // Copyright 2020 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package middleware |
| |
| import ( |
| "encoding/json" |
| "hash/fnv" |
| "io" |
| "net/http" |
| "net/http/httptest" |
| "testing" |
| "time" |
| |
| "github.com/google/go-cmp/cmp" |
| "github.com/google/go-cmp/cmp/cmpopts" |
| ) |
| |
| func TestStats(t *testing.T) { |
| data := []byte("this is the data we are going to serve") |
| const code = 218 |
| ts := httptest.NewServer(Stats()(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| ctx := r.Context() |
| w.WriteHeader(code) |
| SetStat(ctx, "a", 1) |
| w.Write(data[:10]) |
| SetStat(ctx, "b", 2) |
| time.Sleep(500 * time.Millisecond) |
| SetStat(ctx, "a", 3) |
| w.Write(data[10:]) |
| }))) |
| defer ts.Close() |
| res, err := ts.Client().Get(ts.URL) |
| if err != nil { |
| t.Fatal(err) |
| } |
| defer res.Body.Close() |
| if res.StatusCode != http.StatusOK { |
| t.Fatalf("failed with status %d", res.StatusCode) |
| } |
| gotData, err := io.ReadAll(res.Body) |
| if err != nil { |
| t.Fatal(err) |
| } |
| var got PageStats |
| if err := json.Unmarshal(gotData, &got); err != nil { |
| t.Fatal(err) |
| } |
| |
| h := fnv.New64a() |
| h.Write(data) |
| want := PageStats{ |
| StatusCode: code, |
| Size: len(data), |
| Hash: h.Sum64(), |
| Other: map[string]any{ |
| // JSON unmarshals all numbers into float64s. |
| "a": []any{float64(1), float64(3)}, |
| "b": float64(2), |
| }, |
| } |
| diff := cmp.Diff(want, got, cmpopts.IgnoreFields(PageStats{}, "MillisToFirstByte", "MillisToLastByte")) |
| if diff != "" { |
| t.Errorf("mismatch (-want, +got):\n%s", diff) |
| } |
| const tolerance = 50 // 50 ms of tolerance for time measurements |
| if g := got.MillisToFirstByte; !within(g, 0, tolerance) { |
| t.Errorf("MillisToFirstByte is %d, wanted 0 - %d", g, tolerance) |
| } |
| if g := got.MillisToLastByte; !within(g, 500, tolerance) { |
| t.Errorf("MillisToLastByte is %d, wanted 500 +/- %d", g, tolerance) |
| } |
| } |
| |
| func within(got, want, tolerance int64) bool { |
| d := got - want |
| if d < 0 { |
| d = -d |
| } |
| return d <= tolerance |
| } |