Apply job outcomes a gateway kept while the cloud was away

A job_event from a gateway moves a job that is still in flight (uploading,
printing, paused) to printing, completed or failed, and is acknowledged
whether or not it changed anything so the gateway stops sending it. A job
the cloud has cancelled, completed or put back in the queue is left alone,
and a gateway can only touch jobs of its own farm. If the database is
unreachable it is not acknowledged, so it is sent again.

scripts/e2e-vendors.sh gains a phase that takes the backend away for the
whole of a fake print and checks the job completes on reconnect from the
proxy's kept record.

tests/late_failure.test.ts

@@ -26,3 +26,26 @@ describe("late start failures", () => {
     expect(takeStart("bulk-1499")).toBe("job-1499");
   });
 });
+
+import { jobStatusFromGatewayEvent } from "../src/dispatch/job_status";
+
+describe("jobStatusFromGatewayEvent", () => {
+  test("a finish is believed for any job still in flight, even one never seen printing", () => {
+    for (const current of ["uploading", "printing", "paused"]) {
+      expect(jobStatusFromGatewayEvent(current, "finished")).toBe("completed");
+      expect(jobStatusFromGatewayEvent(current, "failed")).toBe("failed");
+    }
+  });
+  test("started only promotes a job that was still uploading", () => {
+    expect(jobStatusFromGatewayEvent("uploading", "started")).toBe("printing");
+    expect(jobStatusFromGatewayEvent("printing", "started")).toBeUndefined();
+    expect(jobStatusFromGatewayEvent("paused", "started")).toBeUndefined();
+  });
+  test("a job the cloud has already settled or taken back is left alone", () => {
+    for (const current of ["queued", "completed", "failed", "cancelled"]) {
+      for (const event of ["started", "finished", "failed"] as const) {
+        expect(jobStatusFromGatewayEvent(current, event)).toBeUndefined();
+      }
+    }
+  });
+});