Tests for assertIsHour()

frontend/devices/__tests__/state_to_props_test.tsx

@@ -1,9 +1,10 @@
 import {
-  fakeFbosConfig, fakeImage, fakeFarmwareEnv
+  fakeFbosConfig, fakeImage, fakeFarmwareEnv, fakeWebAppConfig
 } from "../../__test_support__/fake_state/resources";
 
 let mockFbosConfig: TaggedFbosConfig | undefined = fakeFbosConfig();
 const mockImages: TaggedImage | undefined = fakeImage();
+const mockWebAppConf = fakeWebAppConfig();
 
 jest.mock("../../resources/selectors_by_kind", () => ({
   selectAllAlerts: () => [],
@@ -17,7 +18,7 @@ jest.mock("../../resources/selectors_by_kind", () => ({
 jest.mock("../../resources/getters", () => ({
   getFbosConfig: () => mockFbosConfig,
   getFirmwareConfig: () => undefined,
-  getWebAppConfig: jest.fn(),
+  getWebAppConfig: jest.fn(() => mockWebAppConf),
 }));
 
 import { mapStateToProps } from "../state_to_props";

frontend/devices/components/fbos_settings/ota_time_selector/__tests__/index_test.tsx

@@ -1,10 +1,19 @@
 import React from "react";
-import { OtaTimeSelector, changeOtaHour } from "..";
+import { OtaTimeSelector, changeOtaHour, assertIsHour } from "..";
 import { shallow } from "enzyme";
 import { FBSelect } from "../../../../../ui";
 import { fakeDevice } from "../../../../../__test_support__/resource_index_builder";
 
 describe("OTA time selector", () => {
+  it("asserts that a variable is an HOUR", () => {
+    expect(assertIsHour(undefined)).toBe(undefined);
+    // tslint:disable-next-line:no-null-keyword
+    expect(assertIsHour(null as unknown as undefined)).toBe(undefined);
+    const crashOn = (x: number) => () => assertIsHour(x);
+    expect(assertIsHour(undefined)).toBe(undefined);
+    expect(crashOn(-2)).toThrowError("Not an hour!");
+    expect(crashOn(24)).toThrowError("Not an hour!");
+  });
   it("selects an OTA update time", () => {
     const onUpdate = jest.fn();
     const el = shallow(<OtaTimeSelector

frontend/devices/components/fbos_settings/ota_time_selector/index.tsx

@@ -112,7 +112,7 @@ export const changeOtaHour =
       dispatch(save(device.uuid));
     };
 
-function assertIsHour(val: number | undefined): asserts val is (HOUR | undefined) {
+export function assertIsHour(val: number | undefined): asserts val is (HOUR | undefined) {
   if ((val === null) || (val === undefined)) {
     return;
   }