diff --git a/test/ExampleWorker.js b/test/ExampleWorker.js
index 791c8085..2b058f89 100644
--- a/test/ExampleWorker.js
+++ b/test/ExampleWorker.js
@@ -2,37 +2,34 @@
 /* eslint no-global-assign: 0 */
 "use strict";
 
-const stubBrowserFeatures = M => {
-  const noop = () => ({ collisionFilter: {}, mouse: {} });
-  M.Render.create = () => ({ options: {}, bounds: { min: { x: 0, y: 0 }, max: { x: 800, y: 600 }}});
-  M.Render.run = M.Render.lookAt = noop;
-  M.Runner.create = M.Runner.run = noop;
-  M.MouseConstraint.create = M.Mouse.create = noop;
-  M.Common.info = M.Common.warn = M.Common.log;
-  return M;
-};
-
-const reset = M => {
-  M.Common._nextId = M.Common._seed = 0;
-  M.Body._nextCollidingGroupId = 1;
-  M.Body._nextNonCollidingGroupId = -1;
-  M.Body._nextCategory = 0x0001;
-};
-
 const mock = require('mock-require');
-const { engineCapture } = require('./TestTools');
-const MatterDev = stubBrowserFeatures(require('../build/matter.dev'));
-const MatterBuild = stubBrowserFeatures(require('../build/matter'));
+const { requireUncached, engineCapture } = require('./TestTools');
 const Example = require('../examples/index');
+const consoleOriginal = global.console;
 
-const runExample = options => {
-  const Matter = options.useDev ? MatterDev : MatterBuild;
-  const consoleOriginal = global.console;
-  const logs = [];
+const prepareMatter = (options) => {
+  const Matter = requireUncached(options.useDev ? '../build/matter.dev' : '../build/matter');
 
+  if (Matter.Common._nextId !== 0) {
+    throw 'Matter instance has already been used.';
+  }
+
+  const noop = () => ({ collisionFilter: {}, mouse: {} });
+
+  Matter.Render.create = () => ({ options: {}, bounds: { min: { x: 0, y: 0 }, max: { x: 800, y: 600 }}});
+  Matter.Render.run = Matter.Render.lookAt = noop;
+  Matter.Runner.create = Matter.Runner.run = noop;
+  Matter.MouseConstraint.create = Matter.Mouse.create = noop;
+  Matter.Common.info = Matter.Common.warn = Matter.Common.log;
+  
+  return Matter;
+};
+
+const prepareEnvironment = Matter => {
   mock('matter-js', Matter);
   global.Matter = Matter;
 
+  const logs = [];
   global.document = global.window = { addEventListener: () => {} };
   global.console = { 
     log: (...args) => {
@@ -40,7 +37,20 @@ const runExample = options => {
     }
   };
 
-  reset(Matter);
+  return logs;
+};
+
+const resetEnvironment = () => {
+  global.console = consoleOriginal;
+  global.window = undefined;
+  global.document = undefined;
+  global.Matter = undefined;
+  mock.stopAll();
+};
+
+const runExample = options => {
+  const Matter = prepareMatter(options);
+  const logs = prepareEnvironment(Matter);
 
   const example = Example[options.name]();
   const engine = example.engine;
@@ -89,11 +99,7 @@ const runExample = options => {
       }
   }
 
-  global.console = consoleOriginal;
-  global.window = undefined;
-  global.document = undefined;
-  global.Matter = undefined;
-  mock.stopAll();
+  resetEnvironment();
 
   return {
     name: options.name,
diff --git a/test/Examples.spec.js b/test/Examples.spec.js
index efb2dc93..00a85dc6 100644
--- a/test/Examples.spec.js
+++ b/test/Examples.spec.js
@@ -5,16 +5,17 @@ jest.setTimeout(30 * 1000);
 
 const fs = require('fs');
 
-const { 
+const {
+    requireUncached,
     comparisonReport, 
     logReport, 
     toMatchExtrinsics, 
     toMatchIntrinsics 
 } = require('./TestTools');
 
-const Example = require('../examples/index');
-const MatterBuild = require('../build/matter');
-const { versionSatisfies } = require('../src/core/Plugin');
+const Example = requireUncached('../examples/index');
+const MatterBuild = requireUncached('../build/matter');
+const { versionSatisfies } = requireUncached('../src/core/Plugin');
 const Worker = require('jest-worker').default;
 
 const testComparison = process.env.COMPARE === 'true';
@@ -30,7 +31,7 @@ const examples = Object.keys(Example).filter(key => {
     return !excluded && supported;
 });
 
-const runExamples = async useDev => {
+const captureExamples = async useDev => {
     const worker = new Worker(require.resolve('./ExampleWorker'), {
         enableWorkerThreads: true,
         numWorkers: 1
@@ -48,8 +49,8 @@ const runExamples = async useDev => {
     return result.reduce((out, capture) => (out[capture.name] = capture, out), {});
 };
 
-const capturesDev = runExamples(true);
-const capturesBuild = runExamples(false);
+const capturesDev = captureExamples(true);
+const capturesBuild = captureExamples(false);
 
 afterAll(async () => {
     // Report experimental capture comparison.
diff --git a/test/TestTools.js b/test/TestTools.js
index 8504adf5..525e547f 100644
--- a/test/TestTools.js
+++ b/test/TestTools.js
@@ -34,6 +34,13 @@ const limit = (val, precision=3) => parseFloat(val.toPrecision(precision));
 const toPercent = val => (100 * val).toPrecision(3);
 const toPercentRound = val => Math.round(100 * val);
 
+const requireUncached = path => {
+    delete require.cache[require.resolve(path)];
+    const module = require(path);
+    delete require.cache[require.resolve(path)];
+    return module;
+};
+
 const noiseThreshold = (val, threshold) => {
     const sign = val < 0 ? -1 : 1;
     const magnitude = Math.abs(val);
@@ -318,6 +325,6 @@ const comparisonReport = (capturesDev, capturesBuild, devSize, buildSize, buildV
 };
 
 module.exports = {
-    engineCapture, comparisonReport, logReport,
+    requireUncached, engineCapture, comparisonReport, logReport,
     toMatchExtrinsics, toMatchIntrinsics
 };
\ No newline at end of file