feat(server/m7-353): coverart.Fetcher MBCAA HTTP client + rate limiter

2026-05-04 14:49:28 -04:00
parent ef6c09dbfb
commit 2d3841966e
2 changed files with 211 additions and 0 deletions
@@ -0,0 +1,109 @@
+package coverart
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestFetcher_Success(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !strings.Contains(r.URL.Path, "/release/abc-123/front-500") {
+			http.Error(w, "wrong path", http.StatusBadRequest)
+			return
+		}
+		w.Header().Set("Content-Type", "image/jpeg")
+		_, _ = w.Write([]byte("FAKE_JPEG"))
+	}))
+	defer srv.Close()
+
+	f := NewFetcher(FetcherConfig{
+		BaseURL:    srv.URL,
+		UserAgent:  "Minstrel/test (https://example.com)",
+		MinPeriod:  0,
+		HTTPClient: srv.Client(),
+	})
+
+	body, err := f.Fetch(context.Background(), "abc-123")
+	if err != nil {
+		t.Fatalf("Fetch: %v", err)
+	}
+	if string(body) != "FAKE_JPEG" {
+		t.Errorf("body = %q, want FAKE_JPEG", string(body))
+	}
+}
+
+func TestFetcher_NotFound(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "not found", http.StatusNotFound)
+	}))
+	defer srv.Close()
+	f := NewFetcher(FetcherConfig{BaseURL: srv.URL, UserAgent: "test", MinPeriod: 0, HTTPClient: srv.Client()})
+	_, err := f.Fetch(context.Background(), "missing")
+	if !errors.Is(err, ErrNotFound) {
+		t.Errorf("err = %v, want ErrNotFound", err)
+	}
+}
+
+func TestFetcher_5xxIsTransient(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		http.Error(w, "boom", http.StatusInternalServerError)
+	}))
+	defer srv.Close()
+	f := NewFetcher(FetcherConfig{BaseURL: srv.URL, UserAgent: "test", MinPeriod: 0, HTTPClient: srv.Client()})
+	_, err := f.Fetch(context.Background(), "any")
+	if !errors.Is(err, ErrTransient) {
+		t.Errorf("err = %v, want ErrTransient", err)
+	}
+}
+
+func TestFetcher_SendsUserAgent(t *testing.T) {
+	var seen string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		seen = r.Header.Get("User-Agent")
+		_, _ = w.Write([]byte("ok"))
+	}))
+	defer srv.Close()
+	f := NewFetcher(FetcherConfig{
+		BaseURL:    srv.URL,
+		UserAgent:  "Minstrel/0.1 (https://example.org)",
+		MinPeriod:  0,
+		HTTPClient: srv.Client(),
+	})
+	_, _ = f.Fetch(context.Background(), "ua-test")
+	if seen != "Minstrel/0.1 (https://example.org)" {
+		t.Errorf("UA = %q", seen)
+	}
+}
+
+func TestFetcher_RateLimitSpacesCalls(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, _ = w.Write([]byte("ok"))
+	}))
+	defer srv.Close()
+	f := NewFetcher(FetcherConfig{
+		BaseURL:    srv.URL,
+		UserAgent:  "test",
+		MinPeriod:  150 * time.Millisecond,
+		HTTPClient: srv.Client(),
+	})
+	start := time.Now()
+	_, _ = f.Fetch(context.Background(), "a")
+	_, _ = f.Fetch(context.Background(), "b")
+	elapsed := time.Since(start)
+	if elapsed < 150*time.Millisecond {
+		t.Errorf("two calls in %v — rate limiter not enforcing", elapsed)
+	}
+}
+
+func TestFetcher_EmptyMBID(t *testing.T) {
+	f := NewFetcher(FetcherConfig{UserAgent: "test", MinPeriod: 0})
+	_, err := f.Fetch(context.Background(), "")
+	if err == nil {
+		t.Error("expected error for empty mbid")
+	}
+}