go-test-sdk-contract-drift-cancel-404

Answer

Root cause. The downstream Go test called /v1/cancel with a session ID it never registered through /v1/process. The upstream SDK (pinned via replace in go.mod) shipped the OpenAPI contract change GAP-DOG-002: its harness handler now has a session-existence guard, so cancel/result on an unknown session returns 404 instead of the old 200. The test asserted 200, so it broke. It's not a flake — it fails solo because the harness state is created fresh per test and the session is simply never there.

Fix. Register the session through the real endpoint first (POST /v1/process), then cancel it — exactly mirroring the SDK's own updated test. This verifies the full path and matches the new contract. Optionally pin the 404 behavior in a second test so drift is caught at the contract boundary, not by surprise later.

// harness handler (SDK side, local replace) — new session-existence guard per GAP-DOG-002
func (h *Harness) Cancel(id string) (int, error) {
    s, ok := h.sessions[id]
    if !ok {
        return http.StatusNotFound, fmt.Errorf("session %q not found", id) // was 200 before
    }
    s.Status = "canceled"
    return http.StatusOK, nil
}

// downstream test — FIXED: register through the real endpoint first
func TestCancelSession(t *testing.T) {
    h := harness.New()

    // Fix: create the session via /v1/process before cancelling it.
    s := h.Process("session-abc123")

    status, err := h.Cancel(s.ID) // full path: register -> cancel
    if err != nil {
        t.Fatalf("unexpected error: %v", err)
    }
    if status != http.StatusOK {
        t.Fatalf("expected 200 for registered session cancel, got %d", status)
    }
}

// Pin the new contract so future drift surfaces here, not in unrelated tests.
func TestCancelUnknownSession404(t *testing.T) {
    h := harness.New()
    status, err := h.Cancel("session-never-registered")
    if err == nil {
        t.Fatal("expected error for unknown session")
    }
    if status != http.StatusNotFound {
        t.Fatalf("expected 404 for unknown session, got %d", status)
    }
}