Add unit tests for util/config.ts

1 files changed, 148 insertions, 0 deletions

diff --git a/src/util/config.test.ts b/src/util/config.test.ts
new file mode 100644
index 0000000..19d7564
--- /dev/null
+++ b/src/util/config.test.ts
@@ -0,0 +1,148 @@
+import { configOrError, handleShutdown } from "./config";
+import { MongoClient } from "mongodb";
+import { Server } from "http";
+
+const exit = jest.spyOn(process, "exit").mockImplementation(() => {
+  throw Error("");
+});
+
+const CommonMocks = {
+  connect: jest.fn(),
+  isConnected: jest.fn(),
+  logout: jest.fn(),
+  watch: jest.fn(),
+  startSession: jest.fn(),
+  withSession: jest.fn(),
+  addListener: jest.fn(),
+  on: jest.fn(),
+  once: jest.fn(),
+  prependListener: jest.fn(),
+  prependOnceListener: jest.fn(),
+  removeAllListeners: jest.fn(),
+  removeListener: jest.fn(),
+  off: jest.fn(),
+  setMaxListeners: jest.fn(),
+  getMaxListeners: jest.fn(),
+  listeners: jest.fn(),
+  listenerCount: jest.fn(),
+  rawListeners: jest.fn(),
+  emit: jest.fn(),
+  eventNames: jest.fn()
+};
+
+const MongoMock = (p: Promise<void>): jest.Mock<MongoClient, void[]> =>
+  jest.fn<MongoClient, void[]>(() => ({
+    ...CommonMocks,
+    close: jest.fn(() => p),
+    db: jest.fn()
+  }));
+const ServerMock = (mockErr: Error | undefined): jest.Mock<Server, void[]> =>
+  jest.fn<Server, void[]>(() => ({
+    ...CommonMocks,
+    connections: 0,
+    setTimeout: jest.fn(),
+    timeout: 0,
+    headersTimeout: 0,
+    keepAliveTimeout: 0,
+    close: function(c: (err?: Error | undefined) => void): Server {
+      c(mockErr);
+      return this;
+    },
+    maxHeadersCount: 0,
+    maxConnections: 0,
+    listen: jest.fn(),
+    listening: true,
+    address: jest.fn(),
+    getConnections: jest.fn(),
+    ref: jest.fn(),
+    unref: jest.fn()
+  }));
+
+describe("configOrError", () => {
+  beforeEach(() => {
+    exit.mockClear();
+  });
+
+  it("should exit when a env var does not exist", () => {
+    // Arrange
+
+    // Act
+    let result;
+    try {
+      result = configOrError("APPLESAUCE");
+    } catch (err) {
+      //
+    }
+
+    // Assert
+    expect(result).toBeUndefined();
+    expect(exit).toHaveBeenCalledWith(1);
+  });
+
+  it("should return the expected env var", () => {
+    // Arrange
+    process.env.CHRYSANTHEMUM = "hello";
+
+    // Act
+    const result = configOrError("CHRYSANTHEMUM");
+
+    // Assert
+    expect(result).toEqual(process.env.CHRYSANTHEMUM);
+    expect(exit).toHaveBeenCalledTimes(0);
+  });
+});
+
+describe("handleShutdown", () => {
+  beforeEach(() => {
+    exit.mockClear();
+    // we don't use the MongoMock or ServerMock to directly test, so no mockClear needed
+  });
+
+  it("should exit gracefully without error", async () => {
+    // Arrange
+    const mongo = MongoMock(new Promise(r => r()))();
+    const server = ServerMock(undefined)();
+
+    // Act
+    try {
+      await handleShutdown(mongo, server)("SIGINT");
+    } catch (err) {
+      //
+    }
+
+    // Assert
+    expect(exit).toHaveBeenCalledWith(1);
+  });
+
+  it("should exit with error with Mongo error", async () => {
+    // Arrange
+    const mongo = MongoMock(new Promise((_, r) => r()))();
+    const server = ServerMock(undefined)();
+
+    // Act
+    try {
+      await handleShutdown(mongo, server)("SIGINT");
+    } catch (err) {
+      //
+    }
+
+    // Assert
+    expect(exit).toHaveBeenCalledWith(1);
+  });
+
+  it("should exit with error with Server error", async () => {
+    // Arrange
+    const mongo = MongoMock(new Promise(r => r()))();
+    const server = ServerMock(Error("oh noooo"))();
+
+    // Act
+    try {
+      await handleShutdown(mongo, server)("SIGINT");
+    } catch (err) {
+      //
+    }
+
+    // Assert
+    expect(exit).toHaveBeenCalledWith(1);
+  });
+});