test(llm): a non-200 is an HTTP status error whose kind carries no body, and the body is bounded (red; adversarial review F3)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/adapters/llm/status_error_test.go

@@ -0,0 +1,63 @@
+package llm
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"git.d-ma.be/mathias/tapir/internal/errkind"
+)
+
+// A non-200 from the gateway is an HTTP status error: its kind can be logged and stored
+// without its body, which can echo the prompt (adversarial review F3).
+
+func failingGateway(t *testing.T, status int, body string) *httptest.Server {
+	t.Helper()
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(status)
+		_, _ = w.Write([]byte(body))
+	}))
+	t.Cleanup(srv.Close)
+	return srv
+}
+
+func TestClient_ANon200IsAnHTTPStatusErrorWhoseKindCarriesNoBody(t *testing.T) {
+	srv := failingGateway(t, http.StatusBadRequest, `{"error":"prompt was: Anders ansvarar för virket"}`)
+
+	_, err := New(srv.URL, "", "m", 5*time.Second).Complete(context.Background(), "s", "u")
+
+	if err == nil {
+		t.Fatal("expected an error")
+	}
+	if got := errkind.Of(err); got != "http_400" {
+		t.Errorf("errkind.Of = %q, want http_400", got)
+	}
+	var he *HTTPError
+	if !errors.As(err, &he) || he.Code != http.StatusBadRequest {
+		t.Errorf("error is not an *HTTPError with the status code: %v", err)
+	}
+}
+
+func TestClient_TheErrorTextIsUnchangedForCallersThatLogIt(t *testing.T) {
+	srv := failingGateway(t, http.StatusBadGateway, "upstream down")
+
+	_, err := New(srv.URL, "", "m", 5*time.Second).Complete(context.Background(), "s", "u")
+
+	if err == nil || err.Error() != "LLM returned 502: upstream down" {
+		t.Errorf("error text = %v: callers that log it already rely on this form", err)
+	}
+}
+
+func TestClient_AnEnormousErrorBodyIsBoundedInTheErrorText(t *testing.T) {
+	srv := failingGateway(t, http.StatusInternalServerError, strings.Repeat("x", 100_000))
+
+	_, err := New(srv.URL, "", "m", 5*time.Second).Complete(context.Background(), "s", "u")
+
+	if err == nil || len(err.Error()) > 1024 {
+		t.Errorf("error text is %d bytes: a gateway's whole body must not become an error message", len(err.Error()))
+	}
+}