Support ES module imports in test files

Author: t-ski

packages/testing/src/Env.ts

@@ -5,6 +5,7 @@ import { FormatError } from "./FormatError";
 import { Args } from "./cli/Args";
 
 import _config from "./config.json";
+import { importDynamically } from "./util";
 
 type TIndexedValue = { [key: string]: unknown };
 
@@ -25,16 +26,10 @@ export class Env {
 	public async call(identifier: string): Promise<void> {
 		if (Args.parseFlag("no-env")) return;
 
-		try {
-			this.api =
-				this.api ?? ((await import(resolvePath(this.rootDirPath, _config.envModuleFilename))) as IEnvApi);
-		} catch (err: unknown) {
-			if ((err as { code: string }).code !== "MODULE_NOT_FOUND") {
-				throw new FormatError(err, `Cannot evaluate environment module '${_config.envModuleFilename}'`);
-			}
-			this.api = {};
-		}
-
+		this.api =
+			this.api ??
+			(await importDynamically<IEnvApi>(resolvePath(this.rootDirPath, _config.envModuleFilename))) ??
+			{};
 		if (!(this.api as TIndexedValue)[identifier]) {
 			return;
 		}

packages/testing/src/api.ts

@@ -7,6 +7,8 @@ import { Env } from "./Env";
 
 import { FormatError } from "./FormatError";
 
+import { importDynamically } from "./util";
+
 import _config from "./config.json";
 
 interface IRecord {
@@ -30,7 +32,7 @@ function traversePath(path: string) {
 
 		importMutex
 			.lock(async () => {
-				await import(filepath);
+				await importDynamically(filepath);
 			})
 			.catch((err: Error) => {
 				throw new FormatError(err, "Cannot evaluate test file");
@@ -89,7 +91,7 @@ export async function init(apiArg: unknown, testTargetPath: string /* , options?
 					const testSuiteModuleReference: string = resolvePath(apiArg);
 					!existsSync(testSuiteModuleReference)
 						? reject(new ReferenceError(`Test suite module not found '${testSuiteModuleReference}'`))
-						: resolve((await import(testSuiteModuleReference)) as TTestApi);
+						: resolve(await importDynamically(testSuiteModuleReference));
 				})
 			: (apiArg as { [key: string]: Test });
 

packages/testing/src/cli/cli.ts

@@ -10,6 +10,7 @@ import { Args } from "./Args";
 import { Printer } from "./Printer";
 
 import OFFICIAL_SUITES from "./suites.json";
+import { importDynamically } from "../util";
 
 async function runSuite(): Promise<IResults> {
 	const commandOrTestSuiteModulePath = Args.parsePositional(0);
@@ -20,7 +21,7 @@ async function runSuite(): Promise<IResults> {
 	}
 
 	if (commandOrTestSuiteModulePath === "gen") {
-		await import("./cli.gen");
+		await importDynamically("./cli.gen");
 
 		return;
 	}
@@ -40,9 +41,10 @@ async function runSuite(): Promise<IResults> {
 	}
 
 	try {
-		const TestClass = Object.values(
-			(await import(testSuiteModuleReference)) as { [s: string]: unknown } | ArrayLike<unknown>
-		)[0] as { suiteTitle: string; suiteColor: TColor };
+		const TestClass = Object.values(await importDynamically(testSuiteModuleReference))[0] as {
+			suiteTitle: string;
+			suiteColor: TColor;
+		};
 		Printer.badge(
 			(TestClass.suiteTitle || "").replace(/( ?test(s)?)?$/i, " tests"),
 			TestClass.suiteColor ?? [225, 225, 225]

packages/testing/src/util.ts

@@ -0,0 +1,11 @@
+export async function importDynamically<T>(reference: string): Promise<T> {
+	let resolvedReference: string;
+	try {
+		resolvedReference = require.resolve(reference);
+	} catch {
+		return null;
+	}
+
+	// eslint-disable-next-line @typescript-eslint/no-implied-eval
+	return (await new Function(`return import("${resolvedReference}")`)()) as T;
+}