run rethnet forking tests in CI

.github/workflows/hardhat-network-forking-rethnet-ci.yml

@@ -0,0 +1,79 @@
+name: Hardhat Network Forking Functionality via Rethnet CI
+
+on:
+  push:
+    branches:
+      - $default-branch
+      - "rethnet/main"
+    paths:
+      - "packages/hardhat-core/**"
+      - "packages/hardhat-common/**"
+      - "config/**"
+      - ".github/workflows/hardhat-network-forking-rethnet-ci.yml"
+      - "config/**"
+      - "crates/**"
+      - "Cargo.toml"
+      - "rust-toolchain"
+  pull_request:
+    branches:
+      - "**"
+    paths:
+      - ".github/workflows/hardhat-network-forking-rethnet-ci.yml"
+      - "packages/hardhat-core/**"
+      - "packages/hardhat-common/**"
+      - "config/**"
+      - "crates/**"
+      - "Cargo.toml"
+      - "rust-toolchain"
+
+env:
+  RUSTFLAGS: -Dwarnings
+
+defaults:
+  run:
+    working-directory: packages/hardhat-core
+
+concurrency:
+  group: ${{github.workflow}}-${{github.ref}}
+  cancel-in-progress: true
+
+jobs:
+  # We should run this tests with multiple configurations
+  # but somehow the requests to Alchemy take much longer when doing that.
+  # As a temporary workaround, we run them with a single config.
+  #
+  # Once we properly refactor Hardhat Network's tests we should
+  # add more configurations (different OS and node versions).
+  #
+  # We should also understand what's going on before blindly refactoring them.
+  test_fork:
+    name: Test Hardhat Network's forking functionality while using the rethnet VM mode
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install Rust (stable)
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          override: true
+          components: rustfmt
+
+      - uses: Swatinem/rust-cache@v2
+
+      - uses: actions/setup-node@v2
+        with:
+          node-version: 14
+          cache: yarn
+      - name: Install
+        run: yarn --frozen-lockfile
+      - name: Run tests
+        env:
+          INFURA_URL: ${{ secrets.INFURA_URL }}
+          ALCHEMY_URL: ${{ secrets.ALCHEMY_URL }}
+          DO_NOT_SET_THIS_ENV_VAR____IS_HARDHAT_CI: true
+          FORCE_COLOR: 3
+          HARDHAT_EXPERIMENTAL_VM_MODE: rethnet
+        run: |
+          yarn build
+          yarn test:forking