try to fix flaky test

__tests__/unit/fetch-client.test.ts

@@ -12,8 +12,6 @@ import {
 } from "../../src";
 import { getDefaultHTTPClientOptions } from "../client";
 
-let fetchClient: FetchClient;
-
 const dummyRequest: HTTPRequest = {
   client_timeout_ms: 10000,
   data: { query: "" },
@@ -33,20 +31,16 @@ const dummyStats = {
 };
 
 describe("fetch client", () => {
-  beforeAll(() => {
-    fetchClient = new FetchClient(getDefaultHTTPClientOptions());
-  });
-
-  afterAll(() => {
-    fetchClient.close();
-  });
-
   beforeEach(() => {
+    jest.resetModules();
     fetchMock.resetMocks();
   });
 
   it("returns a valid query response on success", async () => {
     expect.assertions(7);
+
+    const fetchClient = new FetchClient(getDefaultHTTPClientOptions());
+
     const expected: QuerySuccess<{ foo: string }> = {
       data: { foo: "bar" },
       summary: "summary",
@@ -73,10 +67,15 @@ describe("fetch client", () => {
       expect(body.query_tags).toEqual(expected.query_tags);
       expect(body.stats).toEqual(expected.stats);
     }
+
+    fetchClient.close()
   });
 
   it("returns a valid query response on failure", async () => {
     expect.assertions(7);
+
+    const fetchClient = new FetchClient(getDefaultHTTPClientOptions());
+
     const expected: QueryFailure = {
       error: {
         code: "invalid_query",
@@ -107,10 +106,15 @@ describe("fetch client", () => {
       expect(body.query_tags).toEqual(expected.query_tags);
       expect(body.stats).toEqual(expected.stats);
     }
+
+    fetchClient.close()
   });
 
   it("returns a NetworkError if fetch rejects", async () => {
     expect.assertions(2);
+
+    const fetchClient = new FetchClient(getDefaultHTTPClientOptions());
+
     fetchMock.mockRejectOnce(new Error("oops"));
     try {
       await fetchClient.request(dummyRequest);
@@ -122,6 +126,8 @@ describe("fetch client", () => {
         expect(e.cause).toBeDefined();
       }
     }
+
+    fetchClient.close()
   });
 
   it("returns a NetworkError if client timeout causes an abort", async () => {
@@ -134,6 +140,8 @@ describe("fetch client", () => {
       const badClient = new FetchClient(getDefaultHTTPClientOptions());
 
       await badClient.request({ ...dummyRequest, client_timeout_ms: 1 });
+
+      badClient.close()
     } catch (e) {
       if (e instanceof NetworkError) {
         expect(e.message).toEqual(