diff --git a/src/vs/workbench/services/environment/browser/environmentService.ts b/src/vs/workbench/services/environment/browser/environmentService.ts
index cc55d7b5288..5497d3f9e11 100644
--- a/src/vs/workbench/services/environment/browser/environmentService.ts
+++ b/src/vs/workbench/services/environment/browser/environmentService.ts
@@ -290,6 +290,9 @@ export class BrowserWorkbenchEnvironmentService implements IWorkbenchEnvironment
 				extensionHostDebugEnvironment.isExtensionDevelopment = true;
 			}
 		}
+		if (this.options.extensionTestsPath) {
+			extensionHostDebugEnvironment.extensionTestsLocationURI = URI.revive(this.options.extensionTestsPath);
+		}
 
 		// Fill in selected extra environmental properties
 		if (this.payload) {
diff --git a/src/vs/workbench/workbench.web.api.ts b/src/vs/workbench/workbench.web.api.ts
index d337f0fd006..685761c86a3 100644
--- a/src/vs/workbench/workbench.web.api.ts
+++ b/src/vs/workbench/workbench.web.api.ts
@@ -321,6 +321,11 @@ interface IWorkbenchConstructionOptions {
 	 */
 	readonly staticExtensions?: ReadonlyArray<IStaticExtension>;
 
+	/**
+	 * Location of a module containing extension tests to run once the workbench is open.
+	 */
+	readonly extensionTestsPath?: URI;
+
 	/**
 	 * [TEMPORARY]: This will be removed soon.
 	 * Enable inlined extensions.