diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 8977de369e..b2f609847b 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -2,10 +2,13 @@ trigger:
   - master
   - next
 
+variables:
+  npm_config_cache: $(Pipeline.Workspace)/.npm
+
 jobs:
   - job: Lint
     pool:
-      vmImage: ubuntu-16.04
+      vmImage: ubuntu-latest
     steps:
       - task: NodeTool@0
         inputs:
@@ -20,10 +23,12 @@ jobs:
           node -v
           npm -v
         displayName: 'Print versions'
-      - task: Npm@1
+      - task: CacheBeta@1
         inputs:
-          command: custom
-          customCommand: ci
+          key: npm | $(Agent.OS) | package-lock.json
+          path: $(npm_config_cache)
+        displayName: 'Cache npm'
+      - script: npm ci
         displayName: 'Install dependencies'
       - script: npm run lint
         displayName: 'Run lint'
@@ -34,10 +39,13 @@ jobs:
 
   - job: Linux
     pool:
-      vmImage: ubuntu-16.04
+      vmImage: ubuntu-latest
     strategy:
-      maxParallel: 5
+      maxParallel: 6
       matrix:
+        node-13:
+          node_version: ^13.0.0
+          webpack_version: latest
         node-12:
           node_version: ^12.0.0
           webpack_version: latest
@@ -50,6 +58,9 @@ jobs:
         node-6:
           node_version: ^6.9.0
           webpack_version: latest
+        node-10-canary:
+          node_version: ^10.13.0
+          webpack_version: next
     steps:
       - task: NodeTool@0
         inputs:
@@ -64,10 +75,12 @@ jobs:
           node -v
           npm -v
         displayName: 'Print versions'
-      - task: Npm@1
+      - task: CacheBeta@1
         inputs:
-          command: custom
-          customCommand: ci
+          key: npm | $(Agent.OS) | package-lock.json
+          path: $(npm_config_cache)
+        displayName: 'Cache npm'
+      - script: npm ci
         displayName: 'Install dependencies'
       - script: npm i webpack@$(webpack_version)
         displayName: 'Install "webpack@$(webpack_version)"'
@@ -85,10 +98,13 @@ jobs:
 
   - job: macOS
     pool:
-      vmImage: macOS-10.14
+      vmImage: macOS-latest
     strategy:
-      maxParallel: 5
+      maxParallel: 6
       matrix:
+        node-13:
+          node_version: ^13.0.0
+          webpack_version: latest
         node-12:
           node_version: ^12.0.0
           webpack_version: latest
@@ -101,6 +117,9 @@ jobs:
         node-6:
           node_version: ^6.9.0
           webpack_version: latest
+        node-10-canary:
+          node_version: ^10.13.0
+          webpack_version: next
     steps:
       - task: NodeTool@0
         inputs:
@@ -115,10 +134,12 @@ jobs:
           node -v
           npm -v
         displayName: 'Print versions'
-      - task: Npm@1
+      - task: CacheBeta@1
         inputs:
-          command: custom
-          customCommand: ci
+          key: npm | $(Agent.OS) | package-lock.json
+          path: $(npm_config_cache)
+        displayName: 'Cache npm'
+      - script: npm ci
         displayName: 'Install dependencies'
       - script: npm i webpack@$(webpack_version)
         displayName: 'Install "webpack@$(webpack_version)"'
@@ -136,10 +157,13 @@ jobs:
 
   - job: Windows
     pool:
-      vmImage: windows-2019
+      vmImage: windows-latest
     strategy:
-      maxParallel: 5
+      maxParallel: 6
       matrix:
+        node-13:
+          node_version: ^13.0.0
+          webpack_version: latest
         node-12:
           node_version: ^12.0.0
           webpack_version: latest
@@ -152,6 +176,9 @@ jobs:
         node-6:
           node_version: ^6.9.0
           webpack_version: latest
+        node-10-canary:
+          node_version: ^10.13.0
+          webpack_version: next
     steps:
       - script: 'git config --global core.autocrlf input'
         displayName: 'Config git core.autocrlf'
@@ -169,10 +196,12 @@ jobs:
           node -v
           npm -v
         displayName: 'Print versions'
-      - task: Npm@1
+      - task: CacheBeta@1
         inputs:
-          command: custom
-          customCommand: ci
+          key: npm | $(Agent.OS) | package-lock.json
+          path: $(npm_config_cache)
+        displayName: 'Cache npm'
+      - script: npm ci
         displayName: 'Install dependencies'
       - script: npm i webpack@$(webpack_version)
         displayName: 'Install "webpack@$(webpack_version)"'
diff --git a/package.json b/package.json
index 55d0e9b7f1..344425e573 100644
--- a/package.json
+++ b/package.json
@@ -114,7 +114,7 @@
     "webpack-cli": "^3.3.10"
   },
   "peerDependencies": {
-    "webpack": "^4.0.0"
+    "webpack": "^4.0.0 || ^5.0.0"
   },
   "author": "Tobias Koppers @sokra",
   "bugs": "https://github.com/webpack/webpack-dev-server/issues",
diff --git a/test/cli/cli.test.js b/test/cli/cli.test.js
index 51114d3dd4..29bd740011 100644
--- a/test/cli/cli.test.js
+++ b/test/cli/cli.test.js
@@ -176,8 +176,9 @@ describe('CLI', () => {
 
   it('should exit the process when SIGINT is detected, even before the compilation is done', (done) => {
     const cliPath = resolve(__dirname, '../../bin/webpack-dev-server.js');
-    const examplePath = resolve(__dirname, '../../examples/cli/public');
-    const cp = execa('node', [cliPath], { cwd: examplePath });
+    const simpleConfig = resolve(__dirname, '../fixtures/simple-config');
+    const cp = execa('node', [cliPath], { cwd: simpleConfig });
+
     let killed = false;
 
     cp.stdout.on('data', () => {
@@ -197,11 +198,13 @@ describe('CLI', () => {
 
   it('should use different random port when multiple instances are started on different processes', (done) => {
     const cliPath = resolve(__dirname, '../../bin/webpack-dev-server.js');
-    const examplePath = resolve(__dirname, '../../examples/cli/public');
+    const simpleConfig = resolve(__dirname, '../fixtures/simple-config');
 
-    const cp = execa('node', [cliPath, '--colors=false'], { cwd: examplePath });
+    const cp = execa('node', [cliPath, '--colors=false'], {
+      cwd: simpleConfig,
+    });
     const cp2 = execa('node', [cliPath, '--colors=false'], {
-      cwd: examplePath,
+      cwd: simpleConfig,
     });
 
     const runtime = {
@@ -220,22 +223,27 @@ describe('CLI', () => {
       const portMatch = /Project is running at http:\/\/localhost:(\d*)\//.exec(
         bits
       );
+
       if (portMatch) {
         runtime.cp.port = portMatch[1];
       }
+
       if (/Compiled successfully/.test(bits)) {
         expect(cp.pid !== 0).toBe(true);
         cp.kill('SIGINT');
       }
     });
+
     cp2.stdout.on('data', (data) => {
       const bits = data.toString();
       const portMatch = /Project is running at http:\/\/localhost:(\d*)\//.exec(
         bits
       );
+
       if (portMatch) {
         runtime.cp2.port = portMatch[1];
       }
+
       if (/Compiled successfully/.test(bits)) {
         expect(cp.pid !== 0).toBe(true);
         cp2.kill('SIGINT');
@@ -249,8 +257,10 @@ describe('CLI', () => {
         done();
       }
     });
+
     cp2.on('exit', () => {
       runtime.cp2.done = true;
+
       if (runtime.cp.done) {
         expect(runtime.cp.port !== runtime.cp2.port).toBe(true);
         done();
diff --git a/test/e2e/ClientOptions.test.js b/test/e2e/ClientOptions.test.js
index ca3ea17057..b0a5b50834 100644
--- a/test/e2e/ClientOptions.test.js
+++ b/test/e2e/ClientOptions.test.js
@@ -324,7 +324,8 @@ describe('Client console.log', () => {
           });
         })
         .then(() => {
-          expect(res).toMatchSnapshot();
+          // Order doesn't matter, maybe we should improve that in future
+          expect(res.sort()).toMatchSnapshot();
           done();
         });
     });
diff --git a/test/e2e/Iframe.test.js b/test/e2e/Iframe.test.js
index 2ec8caf628..fa46c88377 100644
--- a/test/e2e/Iframe.test.js
+++ b/test/e2e/Iframe.test.js
@@ -84,7 +84,8 @@ describe('Client iframe console.log', () => {
           });
         })
         .then(() => {
-          expect(res).toMatchSnapshot();
+          // Order doesn't matter, maybe we should improve that in future
+          expect(res.sort()).toMatchSnapshot();
           done();
         });
     });
diff --git a/test/e2e/__snapshots__/ClientOptions.test.js.snap b/test/e2e/__snapshots__/ClientOptions.test.js.snap
index d12069f13d..27b5c3406b 100644
--- a/test/e2e/__snapshots__/ClientOptions.test.js.snap
+++ b/test/e2e/__snapshots__/ClientOptions.test.js.snap
@@ -15,8 +15,8 @@ Array [
 
 exports[`Client console.log hot enabled 1`] = `
 Array [
-  "[HMR] Waiting for update signal from WDS...",
   "Hey.",
+  "[HMR] Waiting for update signal from WDS...",
   "[WDS] Hot Module Replacement enabled.",
   "[WDS] Live Reloading enabled.",
 ]
diff --git a/test/e2e/__snapshots__/Iframe.test.js.snap b/test/e2e/__snapshots__/Iframe.test.js.snap
index d66c695eb9..ba2007f1ca 100644
--- a/test/e2e/__snapshots__/Iframe.test.js.snap
+++ b/test/e2e/__snapshots__/Iframe.test.js.snap
@@ -15,8 +15,8 @@ Array [
 
 exports[`Client iframe console.log hot enabled 1`] = `
 Array [
-  "[HMR] Waiting for update signal from WDS...",
   "Hey.",
+  "[HMR] Waiting for update signal from WDS...",
   "[WDS] Hot Module Replacement enabled.",
   "[WDS] Live Reloading enabled.",
 ]
diff --git a/test/server/Server.test.js b/test/server/Server.test.js
index d54712a087..ca041b7795 100644
--- a/test/server/Server.test.js
+++ b/test/server/Server.test.js
@@ -39,9 +39,9 @@ describe('Server', () => {
           return relative('.', p).split(sep);
         })
       ).toMatchSnapshot();
-      expect(
-        server.middleware.context.compiler.options.plugins
-      ).toMatchSnapshot();
+      expect(server.middleware.context.compiler.options.plugins).toEqual([
+        new webpack.HotModuleReplacementPlugin(),
+      ]);
 
       compiler.hooks.done.tap('webpack-dev-server', () => {
         server.close(done);
@@ -64,9 +64,9 @@ describe('Server', () => {
           return relative('.', p).split(sep);
         })
       ).toMatchSnapshot();
-      expect(
-        server.middleware.context.compiler.options.plugins
-      ).toMatchSnapshot();
+      expect(server.middleware.context.compiler.options.plugins).toEqual([
+        new webpack.HotModuleReplacementPlugin(),
+      ]);
 
       compiler.hooks.done.tap('webpack-dev-server', () => {
         server.close(done);
@@ -78,14 +78,6 @@ describe('Server', () => {
 
   // issue: https://github.com/webpack/webpack-dev-server/issues/1724
   describe('express.static.mine.types', () => {
-    beforeEach(() => {
-      jest.resetModules();
-    });
-
-    afterEach(() => {
-      jest.unmock('express');
-    });
-
     it("should success even if mine.types doesn't exist", (done) => {
       jest.mock('express', () => {
         const data = jest.requireActual('express');
@@ -118,31 +110,6 @@ describe('Server', () => {
     });
   });
 
-  describe('WEBPACK_DEV_SERVER environment variable', () => {
-    const OLD_ENV = process.env;
-
-    beforeEach(() => {
-      // this is important - it clears the cache
-      jest.resetModules();
-
-      process.env = { ...OLD_ENV };
-
-      delete process.env.WEBPACK_DEV_SERVER;
-    });
-
-    afterEach(() => {
-      process.env = OLD_ENV;
-    });
-
-    it('should be present', () => {
-      expect(process.env.WEBPACK_DEV_SERVER).toBeUndefined();
-
-      require('../../lib/Server');
-
-      expect(process.env.WEBPACK_DEV_SERVER).toBe(true);
-    });
-  });
-
   describe('Invalidate Callback', () => {
     describe('Testing callback functions on calling invalidate without callback', () => {
       it('should be `noop` (the default callback function)', (done) => {
@@ -178,4 +145,29 @@ describe('Server', () => {
       });
     });
   });
+
+  describe('WEBPACK_DEV_SERVER environment variable', () => {
+    const OLD_ENV = process.env;
+
+    beforeEach(() => {
+      // this is important - it clears the cache
+      jest.resetModules();
+
+      process.env = { ...OLD_ENV };
+
+      delete process.env.WEBPACK_DEV_SERVER;
+    });
+
+    afterEach(() => {
+      process.env = OLD_ENV;
+    });
+
+    it('should be present', () => {
+      expect(process.env.WEBPACK_DEV_SERVER).toBeUndefined();
+
+      require('../../lib/Server');
+
+      expect(process.env.WEBPACK_DEV_SERVER).toBe(true);
+    });
+  });
 });
diff --git a/test/server/__snapshots__/Server.test.js.snap b/test/server/__snapshots__/Server.test.js.snap
index b39da65eb6..6b69e950ff 100644
--- a/test/server/__snapshots__/Server.test.js.snap
+++ b/test/server/__snapshots__/Server.test.js.snap
@@ -19,17 +19,6 @@ Array [
 ]
 `;
 
-exports[`Server addEntries add hot option 2`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
-
 exports[`Server addEntries add hotOnly option 1`] = `
 Array [
   Array [
@@ -48,14 +37,3 @@ Array [
   ],
 ]
 `;
-
-exports[`Server addEntries add hotOnly option 2`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
diff --git a/test/server/__snapshots__/stats-option.test.js.snap b/test/server/__snapshots__/stats-option.test.js.snap
index b5405f897e..5360f60162 100644
--- a/test/server/__snapshots__/stats-option.test.js.snap
+++ b/test/server/__snapshots__/stats-option.test.js.snap
@@ -2,55 +2,55 @@
 
 exports[`stats option should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors') 1`] = `
 Array [
-  "errors",
-  "warnings",
-  "hash",
-  "assetsByChunkName",
   "assets",
+  "assetsByChunkName",
+  "errors",
   "filteredAssets",
+  "hash",
+  "warnings",
 ]
 `;
 
 exports[`stats option should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors') 2`] = `
 Array [
-  "errors",
-  "warnings",
-  "hash",
-  "assetsByChunkName",
   "assets",
+  "assetsByChunkName",
+  "errors",
   "filteredAssets",
+  "hash",
+  "warnings",
 ]
 `;
 
 exports[`stats option should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors') 3`] = `
 Array [
-  "errors",
-  "warnings",
-  "hash",
-  "assetsByChunkName",
   "assets",
+  "assetsByChunkName",
+  "errors",
   "filteredAssets",
+  "hash",
+  "warnings",
 ]
 `;
 
 exports[`stats option should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors') 4`] = `
 Array [
-  "errors",
-  "warnings",
-  "hash",
-  "assetsByChunkName",
   "assets",
+  "assetsByChunkName",
+  "errors",
   "filteredAssets",
+  "hash",
+  "warnings",
 ]
 `;
 
 exports[`stats option should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors') 5`] = `
 Array [
-  "errors",
-  "warnings",
-  "hash",
-  "assetsByChunkName",
   "assets",
+  "assetsByChunkName",
+  "errors",
   "filteredAssets",
+  "hash",
+  "warnings",
 ]
 `;
diff --git a/test/server/inline-option.test.js b/test/server/inline-option.test.js
index 78344621e6..0bbf89de63 100644
--- a/test/server/inline-option.test.js
+++ b/test/server/inline-option.test.js
@@ -27,7 +27,7 @@ describe('inline option', () => {
     afterAll(testServer.close);
 
     it('should include inline client script in the bundle', (done) => {
-      const url = new RegExp(`client/index.js\\?http://0.0.0.0:${port}`);
+      const url = new RegExp(`client(/index.js)?\\?http://0.0.0.0:${port}`);
 
       req.get('/main.js').expect(200, url, done);
     });
@@ -54,7 +54,7 @@ describe('inline option', () => {
     afterAll(testServer.close);
 
     it('should include inline client script in the bundle', (done) => {
-      const url = new RegExp(`client/index.js\\?http://0.0.0.0:${port}`);
+      const url = new RegExp(`client(/index.js)?\\?http://0.0.0.0:${port}`);
 
       req.get('/main.js').expect(200, url, done);
     });
@@ -77,11 +77,14 @@ describe('inline option', () => {
     afterAll(testServer.close);
 
     it('should NOT include inline client script in the bundle', (done) => {
+      const url = new RegExp(`client(/index.js)?\\?http://0.0.0.0:${port}`);
+
       req
         .get('/main.js')
         .expect(200)
         .then(({ text }) => {
-          expect(text.includes(`client/index.js?http://0.0.0.0:${port}`));
+          expect(url.test(text)).toBe(false);
+
           done();
         });
     });
diff --git a/test/server/stats-option.test.js b/test/server/stats-option.test.js
index dc89702cc8..bd71095ced 100644
--- a/test/server/stats-option.test.js
+++ b/test/server/stats-option.test.js
@@ -25,7 +25,7 @@ describe('stats option', () => {
           const server = new Server(compiler, { stats, port, quiet: true });
 
           compiler.hooks.done.tap('webpack-dev-server', (s) => {
-            expect(Object.keys(server.getStats(s))).toMatchSnapshot();
+            expect(Object.keys(server.getStats(s)).sort()).toMatchSnapshot();
 
             server.close(resolve);
           });
@@ -51,7 +51,15 @@ describe('stats option', () => {
       const output = server.getStats(s);
 
       expect(output.warnings.length).toBe(1);
-      expect(output.warnings[0]).toBe('another warning');
+
+      // Webpack@4
+      if (typeof output.warnings[0] === 'string') {
+        expect(output.warnings[0]).toBe('another warning');
+      }
+      // Webpack@5
+      else {
+        expect(output.warnings[0]).toEqual({ message: 'another warning' });
+      }
 
       server.close(done);
     });
diff --git a/test/server/utils/__snapshots__/updateCompiler.test.js.snap b/test/server/utils/__snapshots__/updateCompiler.test.js.snap
deleted file mode 100644
index d922651e48..0000000000
--- a/test/server/utils/__snapshots__/updateCompiler.test.js.snap
+++ /dev/null
@@ -1,47 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`updateCompiler multi compiler config, hot and inline should apply plugins 1`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
-
-exports[`updateCompiler multi compiler config, hot and inline should apply plugins 2`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
-
-exports[`updateCompiler simple config with HMR already, hot and inline should apply plugins 1`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
-
-exports[`updateCompiler simple config, hot and inline should apply plugins 1`] = `
-Array [
-  HotModuleReplacementPlugin {
-    "fullBuildTimeout": 200,
-    "multiStep": undefined,
-    "options": Object {},
-    "requestTimeout": 10000,
-  },
-]
-`;
-
-exports[`updateCompiler simple config, inline should apply plugins without HMR 1`] = `undefined`;
diff --git a/test/server/utils/updateCompiler.test.js b/test/server/utils/updateCompiler.test.js
index 796bc543d4..4203a6f4a6 100644
--- a/test/server/utils/updateCompiler.test.js
+++ b/test/server/utils/updateCompiler.test.js
@@ -6,14 +6,14 @@ const updateCompiler = require('../../../lib/utils/updateCompiler');
 describe('updateCompiler', () => {
   describe('simple config, inline', () => {
     let compiler;
+
     beforeAll(() => {
       const webpackConfig = require('../../fixtures/simple-config/webpack.config');
+
       compiler = webpack(webpackConfig);
     });
 
     it('should apply plugins without HMR', () => {
-      const spy = jest.spyOn(compiler.hooks.entryOption, 'call');
-
       updateCompiler(compiler, {
         transportMode: {
           server: 'sockjs',
@@ -24,6 +24,7 @@ describe('updateCompiler', () => {
 
       let tapsByHMR = 0;
       let tapsByProvidePlugin = 0;
+
       compiler.hooks.compilation.taps.forEach((tap) => {
         if (tap.name === 'HotModuleReplacementPlugin') {
           tapsByHMR += 1;
@@ -32,26 +33,23 @@ describe('updateCompiler', () => {
         }
       });
 
-      expect(spy).toHaveBeenCalledTimes(1);
+      expect(compiler.hooks.entryOption.taps.length).toBe(1);
       expect(tapsByHMR).toEqual(0);
       expect(tapsByProvidePlugin).toEqual(1);
-      // should be empty
-      expect(compiler.options.plugins).toMatchSnapshot();
-
-      spy.mockRestore();
+      expect(compiler.options.plugins).toBeUndefined();
     });
   });
 
   describe('simple config, hot and inline', () => {
     let compiler;
+
     beforeAll(() => {
       const webpackConfig = require('../../fixtures/simple-config/webpack.config');
+
       compiler = webpack(webpackConfig);
     });
 
     it('should apply plugins', () => {
-      const spy = jest.spyOn(compiler.hooks.entryOption, 'call');
-
       updateCompiler(compiler, {
         transportMode: {
           server: 'sockjs',
@@ -63,6 +61,7 @@ describe('updateCompiler', () => {
 
       let tapsByHMR = 0;
       let tapsByProvidePlugin = 0;
+
       compiler.hooks.compilation.taps.forEach((tap) => {
         if (tap.name === 'HotModuleReplacementPlugin') {
           tapsByHMR += 1;
@@ -71,26 +70,27 @@ describe('updateCompiler', () => {
         }
       });
 
-      expect(spy).toHaveBeenCalledTimes(1);
+      expect(compiler.hooks.entryOption.taps.length).toBe(1);
       expect(tapsByHMR).toEqual(1);
       expect(tapsByProvidePlugin).toEqual(1);
-      expect(compiler.options.plugins).toMatchSnapshot();
-
-      spy.mockRestore();
+      expect(compiler.options.plugins).toEqual([
+        new webpack.HotModuleReplacementPlugin(),
+      ]);
     });
   });
 
   describe('simple config with HMR already, hot and inline', () => {
     let compiler;
+
     beforeAll(() => {
       const webpackConfig = require('../../fixtures/simple-config/webpack.config');
+
       webpackConfig.plugins = [new webpack.HotModuleReplacementPlugin()];
+
       compiler = webpack(webpackConfig);
     });
 
     it('should apply plugins', () => {
-      const spy = jest.spyOn(compiler.hooks.entryOption, 'call');
-
       updateCompiler(compiler, {
         transportMode: {
           server: 'sockjs',
@@ -102,6 +102,7 @@ describe('updateCompiler', () => {
 
       let tapsByHMR = 0;
       let tapsByProvidePlugin = 0;
+
       compiler.hooks.compilation.taps.forEach((tap) => {
         if (tap.name === 'HotModuleReplacementPlugin') {
           tapsByHMR += 1;
@@ -110,29 +111,27 @@ describe('updateCompiler', () => {
         }
       });
 
-      expect(spy).toHaveBeenCalledTimes(1);
+      expect(compiler.hooks.entryOption.taps.length).toBe(1);
       expect(tapsByHMR).toEqual(1);
       expect(tapsByProvidePlugin).toEqual(1);
-      expect(compiler.options.plugins).toMatchSnapshot();
-
-      spy.mockRestore();
+      expect(compiler.options.plugins).toEqual([
+        new webpack.HotModuleReplacementPlugin(),
+      ]);
     });
   });
 
   describe('multi compiler config, hot and inline', () => {
     let multiCompiler;
+
     beforeAll(() => {
       const webpackConfig = require('../../fixtures/multi-compiler-2-config/webpack.config');
+
       webpackConfig[1].plugins = [new webpack.HotModuleReplacementPlugin()];
+
       multiCompiler = webpack(webpackConfig);
     });
 
     it('should apply plugins', () => {
-      const spies = [];
-      multiCompiler.compilers.forEach((compiler) => {
-        spies.push(jest.spyOn(compiler.hooks.entryOption, 'call'));
-      });
-
       updateCompiler(multiCompiler, {
         transportMode: {
           server: 'sockjs',
@@ -142,14 +141,10 @@ describe('updateCompiler', () => {
         hot: true,
       });
 
-      spies.forEach((spy) => {
-        expect(spy).toHaveBeenCalledTimes(1);
-        spy.mockRestore();
-      });
-
       multiCompiler.compilers.forEach((compiler) => {
         let tapsByHMR = 0;
         let tapsByProvidePlugin = 0;
+
         compiler.hooks.compilation.taps.forEach((tap) => {
           if (tap.name === 'HotModuleReplacementPlugin') {
             tapsByHMR += 1;
@@ -157,9 +152,13 @@ describe('updateCompiler', () => {
             tapsByProvidePlugin += 1;
           }
         });
+
+        expect(compiler.hooks.entryOption.taps.length).toBe(1);
         expect(tapsByHMR).toEqual(1);
         expect(tapsByProvidePlugin).toEqual(1);
-        expect(compiler.options.plugins).toMatchSnapshot();
+        expect(compiler.options.plugins).toEqual([
+          new webpack.HotModuleReplacementPlugin(),
+        ]);
       });
     });
   });