| 1 | package main |
| 2 | |
| 3 | // The ≈ display's rate snapshot (fx.go): fetch, parse, last-good fallback, |
| 4 | // and the empty-until-fetched public shape. |
| 5 | |
| 6 | import ( |
| 7 | "encoding/json" |
| 8 | "net/http" |
| 9 | "net/http/httptest" |
| 10 | "testing" |
| 11 | ) |
| 12 | |
| 13 | const ecbSample = `<?xml version="1.0" encoding="UTF-8"?> |
| 14 | <gesmes:Envelope xmlns:gesmes="http://www.gesmes.org/xml/2002-08-01" xmlns="http://www.ecb.int/vocabulary/2002-08-01/eurofxref"> |
| 15 | <gesmes:subject>Reference rates</gesmes:subject> |
| 16 | <Cube> |
| 17 | <Cube time="2026-07-17"> |
| 18 | <Cube currency="USD" rate="1.0876"/> |
| 19 | <Cube currency="GBP" rate="0.8433"/> |
| 20 | <Cube currency="JPY" rate="170.61"/> |
| 21 | </Cube> |
| 22 | </Cube> |
| 23 | </gesmes:Envelope>` |
| 24 | |
| 25 | func TestFXRefreshAndServe(t *testing.T) { |
| 26 | feed := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 27 | w.Write([]byte(ecbSample)) |
| 28 | })) |
| 29 | defer feed.Close() |
| 30 | ts, s := newTestServer(t) |
| 31 | |
| 32 | get := func() (string, map[string]float64) { |
| 33 | t.Helper() |
| 34 | resp, err := http.Get(ts.URL + "/api/fx") |
| 35 | if err != nil { |
| 36 | t.Fatal(err) |
| 37 | } |
| 38 | defer resp.Body.Close() |
| 39 | if resp.StatusCode != http.StatusOK { |
| 40 | t.Fatalf("fx: HTTP %d", resp.StatusCode) |
| 41 | } |
| 42 | var body struct { |
| 43 | Base string `json:"base"` |
| 44 | Date string `json:"date"` |
| 45 | Rates map[string]float64 `json:"rates"` |
| 46 | } |
| 47 | if err := json.NewDecoder(resp.Body).Decode(&body); err != nil { |
| 48 | t.Fatal(err) |
| 49 | } |
| 50 | if body.Base != "EUR" { |
| 51 | t.Fatalf("base = %q", body.Base) |
| 52 | } |
| 53 | return body.Date, body.Rates |
| 54 | } |
| 55 | |
| 56 | // Before any fetch: an empty snapshot, still a clean 200 (the client just |
| 57 | // shows no ≈ figure). |
| 58 | if date, rates := get(); date != "" || len(rates) != 0 { |
| 59 | t.Fatalf("pre-fetch snapshot = %q %v, want empty", date, rates) |
| 60 | } |
| 61 | |
| 62 | if err := s.fx.refresh(http.DefaultClient, feed.URL); err != nil { |
| 63 | t.Fatal(err) |
| 64 | } |
| 65 | date, rates := get() |
| 66 | if date != "2026-07-17" || rates["USD"] != 1.0876 || rates["GBP"] != 0.8433 || len(rates) != 3 { |
| 67 | t.Fatalf("snapshot = %q %v", date, rates) |
| 68 | } |
| 69 | |
| 70 | // A failing feed keeps the last-good snapshot. |
| 71 | feed.Close() |
| 72 | if err := s.fx.refresh(http.DefaultClient, feed.URL); err == nil { |
| 73 | t.Fatal("refresh against a dead feed reported success") |
| 74 | } |
| 75 | if date, rates := get(); date != "2026-07-17" || len(rates) != 3 { |
| 76 | t.Fatalf("post-failure snapshot = %q %v, want last-good kept", date, rates) |
| 77 | } |
| 78 | |
| 79 | // So does a feed that answers but parses to nothing. |
| 80 | empty := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { |
| 81 | w.Write([]byte(`<Envelope><Cube><Cube time="2026-07-18"></Cube></Cube></Envelope>`)) |
| 82 | })) |
| 83 | defer empty.Close() |
| 84 | if err := s.fx.refresh(http.DefaultClient, empty.URL); err == nil { |
| 85 | t.Fatal("empty feed reported success") |
| 86 | } |
| 87 | if date, _ := get(); date != "2026-07-17" { |
| 88 | t.Fatalf("empty feed replaced the snapshot (date %q)", date) |
| 89 | } |
| 90 | } |
| 91 | |
amadan