feat: 8s backoff cap, scheduled production smoke

Aligns the retry backoff cap with the other spoo SDKs. The daily smoke
runs behind the smoke build tag against production: create, per-link
stats, emoji catalogue, delete.

Author: Zingzy

.github/workflows/smoke.yml

@@ -0,0 +1,30 @@
+name: Production smoke
+
+# Runs the SDK against production daily behind the smoke build tag:
+# create, per-link stats, emoji catalogue, delete. Requires the
+# SPOO_SMOKE_API_KEY secret (dedicated low-scope key).
+on:
+  schedule:
+    - cron: "20 3 * * *"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  smoke:
+    runs-on: ubuntu-latest
+    if: github.repository == 'spoo-me/spoo-go'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+
+      - name: Set up Go
+        uses: actions/setup-go@v6
+        with:
+          go-version: stable
+
+      - name: Smoke against production
+        env:
+          SPOO_SMOKE_API_KEY: ${{ secrets.SPOO_SMOKE_API_KEY }}
+        run: go test -tags smoke -run TestProdSmoke -v -count=1 .

internal/transport/transport.go

@@ -17,7 +17,7 @@ const (
 	// RetryBaseDelay is the exponential-backoff unit.
 	RetryBaseDelay = 500 * time.Millisecond
 	// retryMaxDelay caps a single computed backoff.
-	retryMaxDelay = 10 * time.Second
+	retryMaxDelay = 8 * time.Second
 )
 
 // IdempotentMethod reports whether an HTTP method is safe to replay

smoke_test.go

@@ -0,0 +1,62 @@
+//go:build smoke
+
+package spoo_test
+
+// Scheduled production smoke: create a link, read its stats, fetch the emoji
+// catalogue, delete the link. Runs only with -tags smoke and a dedicated
+// low-scope key in SPOO_SMOKE_API_KEY; it is not part of the offline suite.
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"testing"
+	"time"
+
+	spoo "github.com/spoo-me/spoo-go"
+	"github.com/spoo-me/spoo-go/option"
+)
+
+func TestProdSmoke(t *testing.T) {
+	key := os.Getenv("SPOO_SMOKE_API_KEY")
+	if key == "" {
+		t.Skip("SPOO_SMOKE_API_KEY not set")
+	}
+	client := spoo.NewClient(
+		option.WithAPIKey(key),
+		option.WithClientTag("sdk-go-smoke"),
+	)
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	link, err := client.Shorten(ctx, spoo.ShortenRequest{
+		LongURL: fmt.Sprintf("https://example.com/?smoke=%d", time.Now().UnixNano()),
+	})
+	if err != nil {
+		t.Fatalf("shorten: %v", err)
+	}
+	defer func() {
+		if err := client.DeleteURL(ctx, link.ID); err != nil {
+			t.Errorf("cleanup delete: %v", err)
+		}
+	}()
+	if link.ShortURL == "" {
+		t.Fatal("shorten: empty short_url")
+	}
+
+	stats, err := client.LinkStats(ctx, link.ID, spoo.StatsQuery{GroupBy: []string{"time"}})
+	if err != nil {
+		t.Fatalf("link stats: %v", err)
+	}
+	if stats.Summary.TotalClicks != 0 {
+		t.Fatalf("link stats: expected 0 clicks on a fresh link, got %d", stats.Summary.TotalClicks)
+	}
+
+	set, err := client.EmojiSet(ctx)
+	if err != nil {
+		t.Fatalf("emoji set: %v", err)
+	}
+	if len(set.Emoji) == 0 {
+		t.Fatal("emoji set: empty catalogue")
+	}
+}