[price-service] Improve and update tests (#521)

* Update/improve existing tests
* Add test for VaaCache + a little refactor
* Add tests for get_vaa endpoint
* Add tests to tilt

Author: ali-behjati

price-service/src/__tests__/listen.test.ts

@@ -0,0 +1,116 @@
+import { VaaConfig, VaaCache } from "../listen";
+
+describe("VAA Cache works", () => {
+  test("Setting and getting works as expected", async () => {
+    const cache = new VaaCache();
+
+    expect(cache.get("a", 3)).toBeUndefined();
+
+    cache.set("a", 1, "a-1");
+
+    expect(cache.get("a", 3)).toBeUndefined();
+
+    cache.set("a", 4, "a-2");
+
+    expect(cache.get("a", 3)).toEqual<VaaConfig>({
+      publishTime: 4,
+      vaa: "a-2",
+    });
+
+    cache.set("a", 10, "a-3");
+
+    // Adding some elements with other keys to make sure
+    // they are not stored separately.
+    cache.set("b", 3, "b-1");
+    cache.set("b", 7, "b-2");
+    cache.set("b", 9, "b-3");
+
+    expect(cache.get("a", 3)).toEqual<VaaConfig>({
+      publishTime: 4,
+      vaa: "a-2",
+    });
+    expect(cache.get("a", 4)).toEqual<VaaConfig>({
+      publishTime: 4,
+      vaa: "a-2",
+    });
+    expect(cache.get("a", 5)).toEqual<VaaConfig>({
+      publishTime: 10,
+      vaa: "a-3",
+    });
+    expect(cache.get("a", 10)).toEqual<VaaConfig>({
+      publishTime: 10,
+      vaa: "a-3",
+    });
+
+    expect(cache.get("b", 3)).toEqual<VaaConfig>({
+      publishTime: 3,
+      vaa: "b-1",
+    });
+    expect(cache.get("b", 4)).toEqual<VaaConfig>({
+      publishTime: 7,
+      vaa: "b-2",
+    });
+
+    // When no item item more recent than asked pubTime is asked it should return undefined
+    expect(cache.get("a", 11)).toBeUndefined();
+    expect(cache.get("b", 10)).toBeUndefined();
+
+    // When the asked pubTime is less than the first existing pubTime we are not sure that
+    // this is the first vaa after that time, so we should return undefined.
+    expect(cache.get("a", 0)).toBeUndefined();
+    expect(cache.get("b", 1)).toBeUndefined();
+    expect(cache.get("b", 2)).toBeUndefined();
+  });
+
+  test("removeExpiredValues clears the old values", async () => {
+    jest.useFakeTimers();
+
+    // TTL of 500 seconds for the cache
+    const cache = new VaaCache(500);
+
+    cache.set("a", 300, "a-1");
+    cache.set("a", 700, "a-2");
+    cache.set("a", 900, "a-3");
+
+    expect(cache.get("a", 300)).toEqual<VaaConfig>({
+      publishTime: 300,
+      vaa: "a-1",
+    });
+
+    expect(cache.get("a", 500)).toEqual<VaaConfig>({
+      publishTime: 700,
+      vaa: "a-2",
+    });
+
+    // Set time to second 1000
+    jest.setSystemTime(1000 * 1000);
+
+    cache.removeExpiredValues();
+
+    expect(cache.get("a", 300)).toBeUndefined();
+    expect(cache.get("a", 500)).toBeUndefined();
+  });
+
+  test("the cache clean loop works", async () => {
+    jest.useFakeTimers();
+
+    // TTL of 500 seconds for the cache and cleanup of every 100 seconds
+    const cache = new VaaCache(500, 100);
+    cache.runRemoveExpiredValuesLoop();
+
+    cache.set("a", 300, "a-1");
+    cache.set("a", 700, "a-2");
+    cache.set("a", 900, "a-3");
+
+    expect(cache.get("a", 900)).toEqual<VaaConfig>({
+      publishTime: 900,
+      vaa: "a-3",
+    });
+
+    // Set time to second 2000. Everything should be evicted from cache now.
+    jest.setSystemTime(2000 * 1000);
+    jest.advanceTimersToNextTimer();
+
+    expect(cache.get("a", 900)).toBeUndefined();
+  });
+});