diff --git a/.circleci/config.yml b/.circleci/config.yml
index aa672c2962..d1ec5977d8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -135,6 +135,8 @@ jobs:
       - run: cd npm_and_yarn/helpers && yarn lint
 
       # Run tests
+      - run: cd npm_and_yarn/helpers && yarn test
+
       - store_test_results:
           path: ~/rspec
       - store_artifacts:
diff --git a/npm_and_yarn/helpers/package.json b/npm_and_yarn/helpers/package.json
index 500e8cfdb5..d84bfd1d46 100644
--- a/npm_and_yarn/helpers/package.json
+++ b/npm_and_yarn/helpers/package.json
@@ -19,6 +19,7 @@
     "eslint-plugin-prettier": "^3.1.0",
     "jest": "^24.9.0",
     "nock": "^11.3.3",
-    "prettier": "^1.18.2"
+    "prettier": "^1.18.2",
+    "rimraf": "^3.0.0"
   }
 }
diff --git a/npm_and_yarn/helpers/test/npm/updater.test.js b/npm_and_yarn/helpers/test/npm/updater.test.js
index 2093ccde0f..b05ab35014 100644
--- a/npm_and_yarn/helpers/test/npm/updater.test.js
+++ b/npm_and_yarn/helpers/test/npm/updater.test.js
@@ -1,6 +1,7 @@
 const path = require("path");
 const os = require("os");
 const fs = require("fs");
+const rimraf = require("rimraf");
 const nock = require("nock");
 const {
   updateDependencyFiles,
@@ -12,29 +13,36 @@ describe("updater", () => {
   let tempDir;
   beforeEach(() => {
     nock("https://registry.npmjs.org")
+      .persist()
       .get("/left-pad")
-      .reply(200, helpers.loadFixture("npm-left-pad.json"));
+      .replyWithFile(
+        200,
+        path.join(__dirname, "fixtures", "npm-left-pad.json"),
+        {
+          "Content-Type": "application/json"
+        }
+      );
 
     tempDir = fs.mkdtempSync(os.tmpdir() + path.sep);
   });
-  afterEach(() => fs.rmdirSync(tempDir));
+  afterEach(() => rimraf.sync(tempDir));
 
-  async function copyDependencies(sourceDir, destDir) {
+  function copyDependencies(sourceDir, destDir) {
     const srcPackageJson = path.join(
       __dirname,
       `fixtures/updater/${sourceDir}/package.json`
     );
-    await fs.copyFile(srcPackageJson, `${destDir}/package.json`);
+    fs.copyFileSync(srcPackageJson, `${destDir}/package.json`);
 
     const srcLockfile = path.join(
       __dirname,
       `fixtures/updater/${sourceDir}/package-lock.json`
     );
-    await fs.copyFile(srcLockfile, `${destDir}/package-lock.json`);
+    fs.copyFileSync(srcLockfile, `${destDir}/package-lock.json`);
   }
 
   it("generates an updated package-lock.json", async () => {
-    await copyDependencies("original", tempDir);
+    copyDependencies("original", tempDir);
 
     const result = await updateDependencyFiles(tempDir, "package-lock.json", [
       {
diff --git a/npm_and_yarn/helpers/test/yarn/updater.test.js b/npm_and_yarn/helpers/test/yarn/updater.test.js
index 8eccc01bfa..903322447f 100644
--- a/npm_and_yarn/helpers/test/yarn/updater.test.js
+++ b/npm_and_yarn/helpers/test/yarn/updater.test.js
@@ -1,43 +1,55 @@
 const path = require("path");
 const os = require("os");
 const fs = require("fs");
+const rimraf = require("rimraf");
 const nock = require("nock");
-const {
-  updateDependencyFiles,
-  updateVersionPattern
-} = require("../../lib/yarn/updater");
+const { updateDependencyFiles } = require("../../lib/yarn/updater");
 const helpers = require("./helpers");
 
 describe("updater", () => {
   let tempDir;
   beforeEach(() => {
     nock("https://registry.yarnpkg.com")
+      .persist()
       .get("/left-pad")
-      .reply(200, helpers.loadFixture("yarnpkg-left-pad.json"));
+      .replyWithFile(
+        200,
+        path.join(__dirname, "fixtures", "yarnpkg-left-pad.json"),
+        {
+          "Content-Type": "application/json"
+        }
+      );
     nock("https://registry.yarnpkg.com")
+      .persist()
       .get("/is-positive")
-      .reply(200, helpers.loadFixture("yarnpkg-is-positive.json"));
+      .replyWithFile(
+        200,
+        path.join(__dirname, "fixtures", "yarnpkg-is-positive.json"),
+        {
+          "Content-Type": "application/json"
+        }
+      );
 
     tempDir = fs.mkdtempSync(os.tmpdir() + path.sep);
   });
-  afterEach(() => fs.rmdirSync(tempDir));
+  afterEach(() => rimraf.sync(tempDir));
 
-  async function copyDependencies(sourceDir, destDir) {
+  function copyDependencies(sourceDir, destDir) {
     const srcPackageJson = path.join(
       __dirname,
       `fixtures/updater/${sourceDir}/package.json`
     );
-    await fs.copyFile(srcPackageJson, `${destDir}/package.json`);
+    fs.copyFileSync(srcPackageJson, `${destDir}/package.json`);
 
     const srcYarnLock = path.join(
       __dirname,
       `fixtures/updater/${sourceDir}/yarn.lock`
     );
-    await fs.copyFile(srcYarnLock, `${destDir}/yarn.lock`);
+    fs.copyFileSync(srcYarnLock, `${destDir}/yarn.lock`);
   }
 
   it("generates an updated yarn.lock", async () => {
-    await copyDependencies("original", tempDir);
+    copyDependencies("original", tempDir);
 
     const result = await updateDependencyFiles(tempDir, [
       {
@@ -52,7 +64,7 @@ describe("updater", () => {
   });
 
   it("doesn't modify existing version comments", async () => {
-    await copyDependencies("with-version-comments", tempDir);
+    copyDependencies("with-version-comments", tempDir);
 
     const result = await updateDependencyFiles(tempDir, [
       {
@@ -66,7 +78,7 @@ describe("updater", () => {
   });
 
   it("doesn't add version comments if they're not already there", async () => {
-    await copyDependencies("original", tempDir);
+    copyDependencies("original", tempDir);
 
     const result = await updateDependencyFiles(tempDir, [
       {
@@ -80,7 +92,7 @@ describe("updater", () => {
   });
 
   it("doesn't show an interactive prompt when resolution fails", async () => {
-    await copyDependencies("original", tempDir);
+    copyDependencies("original", tempDir);
 
     expect.assertions(1);
     try {
diff --git a/npm_and_yarn/helpers/yarn.lock b/npm_and_yarn/helpers/yarn.lock
index 734f32b64c..d25f58e990 100644
--- a/npm_and_yarn/helpers/yarn.lock
+++ b/npm_and_yarn/helpers/yarn.lock
@@ -5347,6 +5347,13 @@ rimraf@2.6.3:
   dependencies:
     glob "^7.1.3"
 
+rimraf@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-3.0.0.tgz#614176d4b3010b75e5c390eb0ee96f6dc0cebb9b"
+  integrity sha512-NDGVxTsjqfunkds7CqsOiEnxln4Bo7Nddl3XhS4pXg5OzwkLqJ971ZVAAnB+DDLnF76N+VnDEiBHaVV8I06SUg==
+  dependencies:
+    glob "^7.1.3"
+
 rsvp@^4.8.4:
   version "4.8.5"
   resolved "https://registry.yarnpkg.com/rsvp/-/rsvp-4.8.5.tgz#c8f155311d167f68f21e168df71ec5b083113734"