do not share the snapshots + tests

Author: ChristopherDedominici

v-next/hardhat-network-helpers/src/internal/network-helpers/helpers/load-fixture.ts

@@ -2,11 +2,10 @@ import type { Fixture, NetworkHelpers, Snapshot } from "../../../types.js";
 
 import { HardhatError } from "@nomicfoundation/hardhat-errors";
 
-let snapshots: Array<Snapshot<any>> = [];
-
 export async function loadFixture<T>(
   networkHelpers: NetworkHelpers,
   fixture: Fixture<T>,
+  snapshots: Array<Snapshot<any>>,
 ): Promise<T> {
   if (fixture.name === "") {
     throw new HardhatError(
@@ -20,10 +19,14 @@ export async function loadFixture<T>(
     try {
       await snapshot.restorer.restore();
 
-      snapshots = snapshots.filter(
+      const filteredSnapshots = snapshots.filter(
         (s) =>
           Number(s.restorer.snapshotId) <= Number(snapshot.restorer.snapshotId),
       );
+
+      // Modify the array by reference
+      snapshots.length = 0;
+      snapshots.push(...filteredSnapshots);
     } catch (e) {
       if (
         HardhatError.isHardhatError(e) &&
@@ -52,6 +55,7 @@ export async function loadFixture<T>(
   }
 }
 
-export function clearSnapshots(): void {
-  snapshots = [];
+export function clearSnapshots(snapshots: Array<Snapshot<any>>): void {
+  // Modify the array by reference
+  snapshots.length = 0;
 }

v-next/hardhat-network-helpers/src/internal/network-helpers/network-helpers.ts

@@ -3,6 +3,7 @@ import type {
   Fixture,
   NetworkHelpers as NetworkHelpersI,
   NumberLike,
+  Snapshot,
   SnapshotRestorer,
 } from "../../types.js";
 import type { EthereumProvider } from "hardhat/types/providers";
@@ -36,6 +37,7 @@ const SUPPORTED_TEST_NETWORKS = ["hardhat", "zksync", "anvil"];
 export class NetworkHelpers implements NetworkHelpersI {
   readonly #provider: EthereumProvider;
   readonly #networkName: string;
+  readonly #snapshots: Array<Snapshot<any>> = [];
 
   #isDevelopmentNetwork: boolean | undefined;
   #version: string | undefined;
@@ -50,7 +52,7 @@ export class NetworkHelpers implements NetworkHelpersI {
   }
 
   public clearSnapshots(): void {
-    clearSnapshots();
+    clearSnapshots(this.#snapshots);
   }
 
   public async dropTransaction(txHash: string): Promise<boolean> {
@@ -74,7 +76,7 @@ export class NetworkHelpers implements NetworkHelpersI {
 
   public async loadFixture<T>(fixture: Fixture<T>): Promise<T> {
     await this.throwIfNotDevelopmentNetwork();
-    return loadFixture(this, fixture);
+    return loadFixture(this, fixture, this.#snapshots);
   }
 
   public async mine(

v-next/hardhat-network-helpers/test/network-helpers/load-fixture.ts

@@ -1,7 +1,7 @@
 import type { NetworkHelpers } from "../../src/types.js";
 
 import assert from "node:assert/strict";
-import { before, describe, it } from "node:test";
+import { before, beforeEach, describe, it } from "node:test";
 
 import {
   assertHardhatInvariant,
@@ -153,4 +153,34 @@ describe("network-helpers - loadFixture", () => {
       {},
     );
   });
+
+  describe("multiple different connections should use different fixtures", () => {
+    // This suite verifies that each new network connection gets its own "snapshots" array.
+    // Because we create a fresh "networkHelpers" instance for every test,
+    // the fixture should run for each test and not be cached across connections.
+
+    let calledCount = 0;
+
+    async function mineBlockFixture() {
+      calledCount++;
+    }
+
+    beforeEach(async () => {
+      ({ networkHelpers } = await initializeNetwork());
+    });
+
+    it("should execute the fixture the first time", async () => {
+      await networkHelpers.loadFixture(mineBlockFixture);
+
+      // Executing the fixture should increment `calledCount` to 1.
+      assert.equal(calledCount, 1);
+    });
+
+    it("should execute the fixture the second time", async () => {
+      await networkHelpers.loadFixture(mineBlockFixture);
+
+      // Loading the fixture again (with a new connection) should increment `calledCount` to 2.
+      assert.equal(calledCount, 2);
+    });
+  });
 });