feat: add GitHub Action (#23)

This PR adds a GitHub Action for installing the PocketIC server and a
test for this GitHub Action.

.github/workflows/pocket-ic-server-action-test.yml

@@ -0,0 +1,48 @@
+on:
+  push:
+    branches:
+      - 'main'
+  pull_request:
+
+jobs:
+  test_pocket_ic_server_action:
+    runs-on: ${{ matrix.os }}
+    name: Test the PocketIC server action (action.yml)
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - version: '5.0.0'
+            expected-version: '5.0.0'
+            os: ubuntu-latest
+          - version: '5.0.0'
+            expected-version: '5.0.0'
+            os: macos-latest
+
+          - expected-version: '6.0.0'
+            os: ubuntu-latest
+          - expected-version: '6.0.0'
+            os: macos-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Install latest PocketIC server and check its version
+        if: "${{ matrix.version == '' }}"
+        uses: ./
+      - name: Install PocketIC server and check its version
+        if: "${{ matrix.version != '' }}"
+        uses: ./
+        with:
+          pocket-ic-server-version: ${{ matrix.version }}
+      - name: Check if the proper PocketIC server version is installed
+        run: |
+          actual_pocket_ic_server_ver="$(${POCKET_IC_BIN} --version)"
+
+          expected_pocket_ic_server_ver="pocket-ic-server ${{ matrix.expected-version }}"
+
+          if [ "$actual_pocket_ic_server_ver" != "$expected_pocket_ic_server_ver" ]; then
+            echo "Error: expected PocketIC server version '$expected_pocket_ic_server_ver', but '$actual_pocket_ic_server_ver' found"
+            exit 1
+          fi
+          echo "PocketIC server version '$actual_pocket_ic_server_ver' was installed correctly"

README.md

@@ -2,9 +2,39 @@
 
 PocketIC is a canister smart contract testing solution for the [Internet Computer](https://internetcomputer.org/).
 
+## GitHub Action
+This repository provides a GitHub Action to set up the PocketIC server.
+
+### Usage
+To use this action in your GitHub workflow, include it as a step in your workflow configuration:
+
+```yml
+jobs:
+  example-job:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+    - name: Install PocketIC server
+      uses: dfinity/pocketic@main
+    - name: Confirm successful installation
+      run: "${POCKET_IC_BIN}" --version
+```
+
+The action is designed to run on both ubuntu- and macos- runners.
+
+### Specifying a PocketIC server version
+You can specify a particular version of the PocketIC server to install using the `pocket-ic-server-version` input:
+
+```yml
+    - name: Install PocketIC server
+      uses: dfinity/pocketic@main
+      with: 
+        pocket-ic-server-version: "6.0.0"
+```
 
 ## Download the PocketIC Server
-You can find the versions of the PocketIC server under the [Releases](https://github.com/dfinity/pocketic/releases) tab on the right.
+Alternatively to using the GitHub Action, you can download the PocketIC server binary for a particular version in the [Releases](https://github.com/dfinity/pocketic/releases) tab on the right.
 For macOS, choose `pocket-ic-x86_64-darwin.gz`, for Linux, choose `pocket-ic-x86_64-linux.gz`.
 
 Save the downloaded file as `pocket-ic.gz`, decompress it, and make it executable:
@@ -14,6 +44,12 @@ gzip -d pocket-ic.gz
 chmod +x pocket-ic
 ```
 
+Finally, export the `POCKET_IC_BIN` environment variable to point to the (absolute) path of the PocketIC server binary:
+
+```bash
+export POCKET_IC_BIN="$(pwd)/pocket-ic"
+```
+
 On **macOS**, you might have to additionally run:
 ```bash
 xattr -dr com.apple.quarantine pocket-ic
@@ -22,7 +58,6 @@ to bypass the developer verification from Apple.
 Alternatively, you can open the `pocket-ic` binary by right clicking on it in the Finder and selecting "Open" from the drop-down menu.
 Then, confirm opening this application by clicking "Open" in the dialog that pops up.
 
-
 ## Using PocketIC
 After completion of above steps, you can verify that everything works by running:
 ```bash

action.yml

@@ -0,0 +1,44 @@
+name: 'Install PocketIC server'
+description: 'Install the PocketIC server at a particular version'
+inputs:
+  pocket-ic-server-version:
+    description: >
+      The PocketIC server version to install.
+      If omitted, the latest version will be installed.
+    default: '6.0.0'
+
+runs:
+  using: composite
+  steps:
+    - name: Install PocketIC server
+      shell: sh
+      run: |
+        export POCKET_IC_VERSION="${{ inputs.pocket-ic-server-version }}"
+
+        echo "POCKET_IC_VERSION is $POCKET_IC_VERSION"
+
+        if [ "${{ runner.os }}" = 'Linux' ]; then
+          export OS="linux"
+        elif [ "${{ runner.os }}" = 'macOS' ]; then
+          export OS="darwin"
+        else
+          echo "Unsupported OS."
+          exit 1
+        fi
+
+        echo "OS is $OS"
+
+        # Retry up to 10 times. Each attempt has 20 seconds total to complete, 5 seconds of which is to connect.
+        # This uses the default retry delay, which starts at 1s and doubles each time, up to 10 min.
+        if $(curl --fail --silent --show-error --location --retry 10 --connect-timeout 5 --max-time 20 --retry-connrefused https://github.com/dfinity/pocketic/releases/download/${POCKET_IC_VERSION}/pocket-ic-x86_64-${OS}.gz -o pocket-ic.gz); then
+          echo "Successfully downloaded PocketIC server."
+        else
+          echo "Failed to download PocketIC server."
+          exit 1
+        fi
+
+        gzip -d pocket-ic.gz
+        chmod +x pocket-ic
+
+        export POCKET_IC_BIN="$(pwd)/pocket-ic"
+        echo "POCKET_IC_BIN=$POCKET_IC_BIN" >> $GITHUB_ENV