export hre reset function for plugin testing

Author: zoeyTM

v-next/hardhat-mocha-test-runner/test/fixture-projects/invalid-mocha-config/hardhat.config.js

@@ -0,0 +1,13 @@
+import type { HardhatUserConfig } from "@ignored/hardhat-vnext/config";
+
+import HardhatMochaPlugin from "../../../src/index.js";
+
+const config: HardhatUserConfig = {
+  plugins: [HardhatMochaPlugin],
+  mocha: {
+    // @ts-expect-error -- testing config validation
+    delay: 123,
+  },
+};
+
+export default config;

v-next/hardhat-mocha-test-runner/test/fixture-projects/invalid-mocha-config/hardhat.config.ts

@@ -1,12 +1,24 @@
 import assert from "node:assert/strict";
-import { describe, it } from "node:test";
+import { describe, it, afterEach } from "node:test";
 
-import { useFixtureProject } from "@nomicfoundation/hardhat-test-utils";
+import { HardhatError } from "@ignored/hardhat-vnext-errors";
+import {
+  assertRejectsWithHardhatError,
+  useFixtureProject,
+} from "@nomicfoundation/hardhat-test-utils";
 
 describe("Hardhat Mocha plugin", () => {
   describe("Success", () => {
     useFixtureProject("test-project");
 
+    afterEach(async () => {
+      const { _resetGlobalHardhatRuntimeEnvironment } = await import(
+        "@ignored/hardhat-vnext"
+      );
+
+      _resetGlobalHardhatRuntimeEnvironment();
+    });
+
     it("should work", async () => {
       const hre = await import("@ignored/hardhat-vnext");
 
@@ -19,10 +31,23 @@ describe("Hardhat Mocha plugin", () => {
   describe("Failure", () => {
     useFixtureProject("invalid-mocha-config");
 
+    afterEach(async () => {
+      const { _resetGlobalHardhatRuntimeEnvironment } = await import(
+        "@ignored/hardhat-vnext"
+      );
+
+      _resetGlobalHardhatRuntimeEnvironment();
+    });
+
     it("should fail", async () => {
-      await assert.rejects(
-        () => import("@ignored/hardhat-vnext"),
-        /Config error in config\.mocha\.delay: Expected boolean, received number/,
+      const errors =
+        "\t* Config error in config.mocha.delay: Expected boolean, received number";
+
+      await assertRejectsWithHardhatError(
+        // @ts-expect-error -- we need to invalidate the import cache to re-import the HRE
+        import("@ignored/hardhat-vnext?config=invalid"),
+        HardhatError.ERRORS.GENERAL.INVALID_CONFIG,
+        { errors },
       );
     });
   });

v-next/hardhat-mocha-test-runner/test/index.ts

@@ -12,6 +12,7 @@ import { createHardhatRuntimeEnvironment } from "./hre.js";
 import {
   getGlobalHardhatRuntimeEnvironment,
   setGlobalHardhatRuntimeEnvironment,
+  resetGlobalHardhatRuntimeEnvironment,
 } from "./internal/global-hre-instance.js";
 import { importUserConfig } from "./internal/helpers/config-loading.js";
 
@@ -38,4 +39,12 @@ export const globalOptions: GlobalOptions = hre.globalOptions;
 export const hooks: HookManager = hre.hooks;
 export const interruptions: UserInterruptionManager = hre.interruptions;
 
+// We need to re-export this function so that plugins can use it.
+export const _resetGlobalHardhatRuntimeEnvironment: typeof resetGlobalHardhatRuntimeEnvironment =
+  function (): void {
+    maybeHre = undefined;
+
+    resetGlobalHardhatRuntimeEnvironment();
+  };
+
 export default hre;