diff --git a/packages/testlab/src/test-sandbox.ts b/packages/testlab/src/test-sandbox.ts
index c8e7723daa80..2138614c17a6 100644
--- a/packages/testlab/src/test-sandbox.ts
+++ b/packages/testlab/src/test-sandbox.ts
@@ -58,6 +58,16 @@ export class TestSandbox {
    */
   async reset(): Promise<void> {
     this.validateInst();
+
+    // Decache files from require's cache so future tests aren't affected incase
+    // a file is recreated in sandbox with the same file name but different
+    // contents after resetting the sandbox.
+    for (const key in require.cache) {
+      if (key.startsWith(this.path)) {
+        delete require.cache[key];
+      }
+    }
+
     await emptyDir(this.path);
   }
 
diff --git a/packages/testlab/test/integration/test-sandbox.integration.ts b/packages/testlab/test/integration/test-sandbox.integration.ts
index e08ee57b9ef8..fc419deee096 100644
--- a/packages/testlab/test/integration/test-sandbox.integration.ts
+++ b/packages/testlab/test/integration/test-sandbox.integration.ts
@@ -5,7 +5,7 @@
 
 import {TestSandbox, expect} from '../..';
 import {resolve} from 'path';
-import {remove, pathExists, readFile} from 'fs-extra';
+import {remove, pathExists, readFile, writeJSON} from 'fs-extra';
 
 describe('TestSandbox integration tests', () => {
   let sandbox: TestSandbox;
@@ -63,6 +63,25 @@ describe('TestSandbox integration tests', () => {
     expect(fileContents.pop()).to.equal(sourceMapString);
   });
 
+  it('resets the sandbox', async () => {
+    const file = 'test.js';
+    const resolvedFile = resolve(__dirname, '../fixtures/test.js');
+    await sandbox.copyFile(resolvedFile);
+    await sandbox.reset();
+    expect(await pathExists(resolve(path, file))).to.be.False();
+  });
+
+  it('decaches files from npm require when sandbox is reset', async () => {
+    const file = 'test.json';
+    await writeJSON(resolve(path, file), {x: 1});
+    const data = require(resolve(path, file));
+    expect(data).to.be.eql({x: 1});
+    await sandbox.reset();
+    await writeJSON(resolve(path, file), {x: 2});
+    const data2 = require(resolve(path, file));
+    expect(data2).to.be.eql({x: 2});
+  });
+
   it('deletes the test sandbox', async () => {
     await sandbox.delete();
     expect(await pathExists(path)).to.be.False();