diff --git a/.github/workflows/workflow.yml b/.github/workflows/workflow.yml
index f6c5448..629953d 100644
--- a/.github/workflows/workflow.yml
+++ b/.github/workflows/workflow.yml
@@ -4,51 +4,130 @@ on:
   pull_request:
     branches:
       - master
+      - releases/**
     paths-ignore:
       - '**.md'
   push:
     branches:
       - master
+      - releases/**
     paths-ignore:
       - '**.md'
 
 jobs:
-  test:
-    name: Test on ${{ matrix.os }}
-
+  # Build and unit test
+  build:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
       fail-fast: false
-
     runs-on: ${{ matrix.os }}
-
     steps:
-    - uses: actions/checkout@v1
-
-    - uses: actions/setup-node@v1
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Setup Node.js
+      uses: actions/setup-node@v1
       with:
         node-version: '12.x'
-
-    - name: Get npm cache directory
+    - name: Determine npm cache directory
       id: npm-cache
       run: |
         echo "::set-output name=dir::$(npm config get cache)"
-
-    - uses: actions/cache@v1
+    - name: Restore npm cache
+      uses: actions/cache@v1
       with:
         path: ${{ steps.npm-cache.outputs.dir }}
         key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
         restore-keys: |
           ${{ runner.os }}-node-
-
     - run: npm ci
-
     - name: Prettier Format Check
       run: npm run format-check
-
     - name: ESLint Check
       run: npm run lint
-
     - name: Build & Test
       run: npm run test
+
+  # End to end save and restore
+  test-save:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Generate files
+      shell: bash
+      run: __tests__/create-cache-files.sh ${{ runner.os }}
+    - name: Save cache
+      uses: ./
+      with:
+        key: test-${{ runner.os }}-${{ github.run_id }}
+        path: test-cache
+  test-restore:
+    needs: test-save
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+      fail-fast: false
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Restore cache
+      uses: ./
+      with:
+        key: test-${{ runner.os }}-${{ github.run_id }}
+        path: test-cache
+    - name: Verify cache
+      shell: bash
+      run: __tests__/verify-cache-files.sh ${{ runner.os }}
+
+  # End to end with proxy
+  test-proxy-save:
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:latest
+      options: --dns 127.0.0.1
+    services:
+      squid-proxy:
+        image: datadog/squid:latest
+        ports:
+          - 3128:3128
+    env:
+      https_proxy: http://squid-proxy:3128
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Generate files
+      run: __tests__/create-cache-files.sh proxy
+    - name: Save cache
+      uses: ./
+      with:
+        key: test-proxy-${{ github.run_id }}
+        path: test-cache
+  test-proxy-restore:
+    needs: test-proxy-save
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:latest
+      options: --dns 127.0.0.1
+    services:
+      squid-proxy:
+        image: datadog/squid:latest
+        ports:
+          - 3128:3128
+    env:
+      https_proxy: http://squid-proxy:3128
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Restore cache
+      uses: ./
+      with:
+        key: test-proxy-${{ github.run_id }}
+        path: test-cache
+    - name: Verify cache
+      run: __tests__/verify-cache-files.sh proxy
\ No newline at end of file
diff --git a/__tests__/create-cache-files.sh b/__tests__/create-cache-files.sh
new file mode 100755
index 0000000..885a5f2
--- /dev/null
+++ b/__tests__/create-cache-files.sh
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# Validate args
+prefix="$1"
+if [ -z "$prefix" ]; then
+  echo "Must supply prefix argument"
+  exit 1
+fi
+
+mkdir test-cache
+echo "$prefix $GITHUB_RUN_ID" > test-cache/test-file.txt
\ No newline at end of file
diff --git a/__tests__/tar.test.ts b/__tests__/tar.test.ts
index d5d9b62..6de03c3 100644
--- a/__tests__/tar.test.ts
+++ b/__tests__/tar.test.ts
@@ -51,7 +51,7 @@ test("extract GNU tar", async () => {
 
         await tar.extractTar(archivePath, targetDirectory);
 
-        expect(execMock).toHaveBeenCalledTimes(2);
+        expect(execMock).toHaveBeenCalledTimes(1);
         expect(execMock).toHaveBeenLastCalledWith(`"tar"`, [
             "-xz",
             "-f",
diff --git a/__tests__/verify-cache-files.sh b/__tests__/verify-cache-files.sh
new file mode 100755
index 0000000..c7b75ae
--- /dev/null
+++ b/__tests__/verify-cache-files.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+# Validate args
+prefix="$1"
+if [ -z "$prefix" ]; then
+  echo "Must supply prefix argument"
+  exit 1
+fi
+
+# Sanity check GITHUB_RUN_ID defined
+if [ -z "$GITHUB_RUN_ID" ]; then
+  echo "GITHUB_RUN_ID not defined"
+  exit 1
+fi
+
+# Verify file exists
+file="test-cache/test-file.txt"
+echo "Checking for $file"
+if [ ! -e $file ]; then
+  echo "File does not exist"
+  exit 1
+fi
+
+# Verify file content
+content="$(cat $file)"
+echo "File content:\n$content"
+if [ -z "$(echo $content | grep --fixed-strings "$prefix $GITHUB_RUN_ID")" ]; then
+  echo "Unexpected file content"
+  exit 1
+fi
\ No newline at end of file
diff --git a/dist/restore/index.js b/dist/restore/index.js
index c90f729..b5e894b 100644
--- a/dist/restore/index.js
+++ b/dist/restore/index.js
@@ -3000,6 +3000,7 @@ const exec_1 = __webpack_require__(986);
 const io = __importStar(__webpack_require__(1));
 const fs_1 = __webpack_require__(747);
 const path = __importStar(__webpack_require__(622));
+const tar = __importStar(__webpack_require__(943));
 function isGnuTar() {
     return __awaiter(this, void 0, void 0, function* () {
         core.debug("Checking tar --version");
@@ -3026,7 +3027,7 @@ function getTarPath(args) {
             if (fs_1.existsSync(systemTar)) {
                 return systemTar;
             }
-            else if (yield isGnuTar()) {
+            else if (yield tar.isGnuTar()) {
                 args.push("--force-local");
             }
         }
diff --git a/dist/save/index.js b/dist/save/index.js
index 76c820c..a90a6e4 100644
--- a/dist/save/index.js
+++ b/dist/save/index.js
@@ -2981,6 +2981,7 @@ const exec_1 = __webpack_require__(986);
 const io = __importStar(__webpack_require__(1));
 const fs_1 = __webpack_require__(747);
 const path = __importStar(__webpack_require__(622));
+const tar = __importStar(__webpack_require__(943));
 function isGnuTar() {
     return __awaiter(this, void 0, void 0, function* () {
         core.debug("Checking tar --version");
@@ -3007,7 +3008,7 @@ function getTarPath(args) {
             if (fs_1.existsSync(systemTar)) {
                 return systemTar;
             }
-            else if (yield isGnuTar()) {
+            else if (yield tar.isGnuTar()) {
                 args.push("--force-local");
             }
         }
diff --git a/src/tar.ts b/src/tar.ts
index dde9b61..00bed5a 100644
--- a/src/tar.ts
+++ b/src/tar.ts
@@ -3,6 +3,7 @@ import { exec } from "@actions/exec";
 import * as io from "@actions/io";
 import { existsSync } from "fs";
 import * as path from "path";
+import * as tar from "./tar";
 
 export async function isGnuTar(): Promise<boolean> {
     core.debug("Checking tar --version");
@@ -28,7 +29,7 @@ async function getTarPath(args: string[]): Promise<string> {
         const systemTar = `${process.env["windir"]}\\System32\\tar.exe`;
         if (existsSync(systemTar)) {
             return systemTar;
-        } else if (await isGnuTar()) {
+        } else if (await tar.isGnuTar()) {
             args.push("--force-local");
         }
     }