diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 4160a1eb3..75cee99b0 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -16,6 +16,7 @@ jobs:
           - 10.x
           - 12.x
           - 14.x
+          - 16.x
     steps:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
@@ -31,4 +32,26 @@ jobs:
       - run: npm install
       - run: npm run lint
       - run: npm run format
-      - run: npm run build && npm run test
+      - run: npm run test
+  integration:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version:
+          - 12.x
+          - 14.x
+          - 16.x
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - name: Cache npm
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
+
+      - run: npm install
+      - run: npm run test:bin
diff --git a/.mocharc.yaml b/.mocharc.yaml
index 932144124..2bb78edfc 100644
--- a/.mocharc.yaml
+++ b/.mocharc.yaml
@@ -1,10 +1,8 @@
 exit: true
 extension:
   - ts
-file:
-  - mocha/setup.ts
 package: ./package.json
 reporter: spec
 require:
   - 'ts-node/register'
-spec: spec/**/*.spec.ts
+  - 'source-map-support/register'
diff --git a/package.json b/package.json
index 25f8d8d7f..888085883 100644
--- a/package.json
+++ b/package.json
@@ -149,7 +149,8 @@
     "format:fix": "prettier --write '**/*.{json,md,ts,yml,yaml}'",
     "lint": "tslint --config tslint.json --project tsconfig.json ",
     "lint:fix": "tslint --config tslint.json --fix --project tsconfig.json",
-    "test": "mocha"
+    "test": "mocha --file ./mocha/setup.ts spec/**/*.spec.ts ",
+    "test:bin": "./scripts/bin-test/run.sh"
   },
   "dependencies": {
     "@types/cors": "^2.8.5",
@@ -180,10 +181,12 @@
     "mock-require": "^3.0.3",
     "mz": "^2.7.0",
     "nock": "^10.0.6",
+    "node-fetch": "^2.6.7",
+    "portfinder": "^1.0.28",
     "prettier": "^1.18.2",
     "semver": "^7.3.5",
     "sinon": "^7.3.2",
-    "ts-node": "^8.3.0",
+    "ts-node": "^10.4.0",
     "tslint": "^5.18.0",
     "tslint-config-prettier": "^1.18.0",
     "tslint-no-unused-expression-chai": "^0.1.4",
diff --git a/scripts/bin-test/mocha-setup.ts b/scripts/bin-test/mocha-setup.ts
new file mode 100644
index 000000000..6dfdc7f9d
--- /dev/null
+++ b/scripts/bin-test/mocha-setup.ts
@@ -0,0 +1,4 @@
+import * as chai from 'chai';
+import * as chaiAsPromised from 'chai-as-promised';
+
+chai.use(chaiAsPromised);
diff --git a/scripts/bin-test/run.sh b/scripts/bin-test/run.sh
new file mode 100755
index 000000000..c3e3da673
--- /dev/null
+++ b/scripts/bin-test/run.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+set -ex # Immediately exit on failure
+
+# Link the Functions SDK for the testing environment.
+npm run build
+npm link
+
+# Link local SDK to all test sources.
+for f in scripts/bin-test/sources/*; do
+    if [ -d "$f" ]; then
+        (cd "$f" && npm link firebase-functions)
+    fi
+done
+
+## DEBUG
+ls -la scripts/bin-test/sources/commonjs/node_modules
+
+mocha \
+  --file ./scripts/bin-test/mocha-setup.ts \
+  ./scripts/bin-test/test.ts
diff --git a/scripts/bin-test/sources/commonjs-grouped/g1.js b/scripts/bin-test/sources/commonjs-grouped/g1.js
new file mode 100644
index 000000000..57766af02
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs-grouped/g1.js
@@ -0,0 +1,9 @@
+const functions = require("firebase-functions");
+
+exports.groupedhttp = functions.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.groupedcallable = functions.https.onCall(() => {
+    return "PASS";
+});
diff --git a/scripts/bin-test/sources/commonjs-grouped/index.js b/scripts/bin-test/sources/commonjs-grouped/index.js
new file mode 100644
index 000000000..b00828de0
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs-grouped/index.js
@@ -0,0 +1,20 @@
+const functions = require("firebase-functions");
+const functionsv2 = require("firebase-functions/v2");
+
+exports.v1http = functions.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v1callable = functions.https.onCall(() => {
+    return "PASS";
+});
+
+exports.v2http = functionsv2.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v2callable = functionsv2.https.onCall(() => {
+    return "PASS";
+});
+
+exports.g1 = require("./g1");
diff --git a/scripts/bin-test/sources/commonjs-grouped/package.json b/scripts/bin-test/sources/commonjs-grouped/package.json
new file mode 100644
index 000000000..1ec99f52f
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs-grouped/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "commonjs-grouped"
+}
diff --git a/scripts/bin-test/sources/commonjs-main/functions.js b/scripts/bin-test/sources/commonjs-main/functions.js
new file mode 100644
index 000000000..9122f9223
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs-main/functions.js
@@ -0,0 +1,18 @@
+const functions = require("firebase-functions");
+const functionsv2 = require("firebase-functions/v2");
+
+exports.v1http = functions.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v1callable = functions.https.onCall(() => {
+    return "PASS";
+});
+
+exports.v2http = functionsv2.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v2callable = functionsv2.https.onCall(() => {
+    return "PASS";
+});
diff --git a/scripts/bin-test/sources/commonjs-main/package.json b/scripts/bin-test/sources/commonjs-main/package.json
new file mode 100644
index 000000000..a781259f8
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs-main/package.json
@@ -0,0 +1,4 @@
+{
+  "name": "commonjs-main",
+  "main": "functions.js"
+}
diff --git a/scripts/bin-test/sources/commonjs/index.js b/scripts/bin-test/sources/commonjs/index.js
new file mode 100644
index 000000000..9122f9223
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs/index.js
@@ -0,0 +1,18 @@
+const functions = require("firebase-functions");
+const functionsv2 = require("firebase-functions/v2");
+
+exports.v1http = functions.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v1callable = functions.https.onCall(() => {
+    return "PASS";
+});
+
+exports.v2http = functionsv2.https.onRequest((req, resp) => {
+    resp.status(200).send("PASS");
+});
+
+exports.v2callable = functionsv2.https.onCall(() => {
+    return "PASS";
+});
diff --git a/scripts/bin-test/sources/commonjs/package.json b/scripts/bin-test/sources/commonjs/package.json
new file mode 100644
index 000000000..30e1b1b27
--- /dev/null
+++ b/scripts/bin-test/sources/commonjs/package.json
@@ -0,0 +1,3 @@
+{
+  "name": "commonjs"
+}
diff --git a/spec/fixtures/sources/esm-ext/index.mjs b/scripts/bin-test/sources/esm-ext/index.mjs
similarity index 76%
rename from spec/fixtures/sources/esm-ext/index.mjs
rename to scripts/bin-test/sources/esm-ext/index.mjs
index 28d538e3b..91e974d93 100644
--- a/spec/fixtures/sources/esm-ext/index.mjs
+++ b/scripts/bin-test/sources/esm-ext/index.mjs
@@ -1,5 +1,5 @@
-import * as functions from '../../../../lib/index.js';
-import * as functionsv2 from "../../../../lib/v2/index.js";
+import * as functions from "firebase-functions";
+import * as functionsv2 from "firebase-functions/v2";
 
 export const v1http = functions.https.onRequest((req, resp) => {
   resp.status(200).send("PASS");
diff --git a/spec/fixtures/sources/esm-ext/package.json b/scripts/bin-test/sources/esm-ext/package.json
similarity index 100%
rename from spec/fixtures/sources/esm-ext/package.json
rename to scripts/bin-test/sources/esm-ext/package.json
diff --git a/spec/fixtures/sources/esm-main/functions.js b/scripts/bin-test/sources/esm-main/functions.js
similarity index 76%
rename from spec/fixtures/sources/esm-main/functions.js
rename to scripts/bin-test/sources/esm-main/functions.js
index d1f98b49a..b09186731 100644
--- a/spec/fixtures/sources/esm-main/functions.js
+++ b/scripts/bin-test/sources/esm-main/functions.js
@@ -1,5 +1,5 @@
-import * as functions from "../../../../lib/index.js";
-import * as functionsv2 from "../../../../lib/v2/index.js";
+import * as functions from "firebase-functions";
+import * as functionsv2 from "firebase-functions/v2";
 
 export const v1http = functions.https.onRequest((req, resp) => {
     resp.status(200).send("PASS");
diff --git a/spec/fixtures/sources/esm-main/package.json b/scripts/bin-test/sources/esm-main/package.json
similarity index 100%
rename from spec/fixtures/sources/esm-main/package.json
rename to scripts/bin-test/sources/esm-main/package.json
diff --git a/spec/fixtures/sources/esm/index.js b/scripts/bin-test/sources/esm/index.js
similarity index 76%
rename from spec/fixtures/sources/esm/index.js
rename to scripts/bin-test/sources/esm/index.js
index d1f98b49a..b09186731 100644
--- a/spec/fixtures/sources/esm/index.js
+++ b/scripts/bin-test/sources/esm/index.js
@@ -1,5 +1,5 @@
-import * as functions from "../../../../lib/index.js";
-import * as functionsv2 from "../../../../lib/v2/index.js";
+import * as functions from "firebase-functions";
+import * as functionsv2 from "firebase-functions/v2";
 
 export const v1http = functions.https.onRequest((req, resp) => {
     resp.status(200).send("PASS");
diff --git a/spec/fixtures/sources/esm/package.json b/scripts/bin-test/sources/esm/package.json
similarity index 100%
rename from spec/fixtures/sources/esm/package.json
rename to scripts/bin-test/sources/esm/package.json
diff --git a/scripts/bin-test/test.ts b/scripts/bin-test/test.ts
new file mode 100644
index 000000000..1c6f1a24e
--- /dev/null
+++ b/scripts/bin-test/test.ts
@@ -0,0 +1,233 @@
+import * as path from 'path';
+import * as subprocess from 'child_process';
+import { promisify } from 'util';
+
+import fetch from 'node-fetch';
+import * as portfinder from 'portfinder';
+import * as yaml from 'js-yaml';
+import * as semver from 'semver';
+import { expect } from 'chai';
+
+const TIMEOUT_XL = 20_000;
+const TIMEOUT_L = 10_000;
+const TIMEOUT_M = 5_000;
+const TIMEOUT_S = 1_000;
+
+const BASE_STACK = {
+  endpoints: {
+    v1http: {
+      platform: 'gcfv1',
+      entryPoint: 'v1http',
+      httpsTrigger: {},
+    },
+    v1callable: {
+      platform: 'gcfv1',
+      entryPoint: 'v1callable',
+      labels: {},
+      callableTrigger: {},
+    },
+    v2http: {
+      platform: 'gcfv2',
+      entryPoint: 'v2http',
+      labels: {},
+      httpsTrigger: {},
+    },
+    v2callable: {
+      platform: 'gcfv2',
+      entryPoint: 'v2callable',
+      labels: {},
+      callableTrigger: {},
+    },
+  },
+  requiredAPIs: [],
+  specVersion: 'v1alpha1',
+};
+
+type Testcase = {
+  name: string;
+  modulePath: string;
+  expected: Record<string, any>;
+};
+
+async function retryUntil(
+  fn: () => Promise<boolean>,
+  timeoutMs: number,
+  sleepMs: number = TIMEOUT_S
+) {
+  const sleep = () => {
+    return new Promise<void>((resolve) => {
+      setTimeout(() => resolve(), sleepMs);
+    });
+  };
+  const timedOut = new Promise<never>((resolve, reject) => {
+    setTimeout(() => {
+      reject(new Error('retry timeout'));
+    }, timeoutMs);
+  });
+  const retry = (async () => {
+    while (true) {
+      if (await fn()) break;
+      await sleep();
+    }
+  })();
+  await Promise.race([retry, timedOut]);
+}
+
+async function startBin(
+  tc: Testcase,
+  debug?: boolean
+): Promise<{ port: number; cleanup: () => Promise<void> }> {
+  const getPort = promisify(portfinder.getPort) as () => Promise<number>;
+  const port = await getPort();
+
+  const proc = subprocess.spawn('./node_modules/.bin/firebase-functions', [], {
+    cwd: path.resolve(tc.modulePath),
+    env: {
+      PATH: process.env.PATH,
+      GLCOUD_PROJECT: 'test-project',
+      STACK_CONTROL_API_PORT: port,
+    },
+  });
+
+  if (!proc) {
+    throw new Error('Failed to start firebase functions');
+  }
+
+  await retryUntil(async () => {
+    try {
+      await fetch(`http://localhost:${port}/__/stack.yaml`);
+    } catch (e) {
+      if (e?.code === 'ECONNREFUSED') {
+        return false;
+      }
+      throw e;
+    }
+    return true;
+  }, TIMEOUT_M);
+
+  if (debug) {
+    proc.stdout?.on('data', (data: unknown) => {
+      console.log(`[${tc.name} stdout] ` + data);
+    });
+
+    proc.stderr?.on('data', (data: unknown) => {
+      console.log(`[${tc.name} stderr] ` + data);
+    });
+  }
+
+  return {
+    port,
+    cleanup: async () => {
+      process.kill(proc.pid);
+      await retryUntil(async () => {
+        try {
+          process.kill(proc.pid, 0);
+        } catch {
+          // process.kill w/ signal 0 will throw an error if the pid no longer exists.
+          return true;
+        }
+        return false;
+      }, TIMEOUT_M);
+    },
+  };
+}
+
+describe('stack.yaml', () => {
+  async function runTests(tc: Testcase) {
+    let port: number;
+    let cleanup: () => Promise<void>;
+
+    before(async () => {
+      const r = await startBin(tc);
+      port = r.port;
+      cleanup = r.cleanup;
+    });
+
+    after(async () => {
+      await cleanup?.();
+    });
+
+    it('stack.yaml returns expected Manifest', async () => {
+      const res = await fetch(`http://localhost:${port}/__/stack.yaml`);
+      const text = await res.text();
+      let parsed: any;
+      try {
+        parsed = yaml.load(text);
+      } catch (err) {
+        throw new Error('Failed to parse stack.yaml ' + err);
+      }
+      expect(parsed).to.be.deep.equal(tc.expected);
+    });
+  }
+
+  describe('commonjs', () => {
+    const testcases: Testcase[] = [
+      {
+        name: 'basic',
+        modulePath: './scripts/bin-test/sources/commonjs',
+        expected: BASE_STACK,
+      },
+      {
+        name: 'has main',
+        modulePath: './scripts/bin-test/sources/commonjs-main',
+        expected: BASE_STACK,
+      },
+      {
+        name: 'grouped',
+        modulePath: './scripts/bin-test/sources/commonjs-grouped',
+        expected: {
+          ...BASE_STACK,
+          endpoints: {
+            ...BASE_STACK.endpoints,
+            'g1-groupedhttp': {
+              platform: 'gcfv1',
+              entryPoint: 'g1.groupedhttp',
+              httpsTrigger: {},
+            },
+            'g1-groupedcallable': {
+              platform: 'gcfv1',
+              entryPoint: 'g1.groupedcallable',
+              labels: {},
+              callableTrigger: {},
+            },
+          },
+        },
+      },
+    ];
+
+    for (const tc of testcases) {
+      describe(tc.name, async () => {
+        await runTests(tc);
+      });
+    }
+  }).timeout(TIMEOUT_L);
+
+  if (semver.gt(process.versions.node, '13.2.0')) {
+    describe('esm', () => {
+      const testcases: Testcase[] = [
+        {
+          name: 'basic',
+          modulePath: './scripts/bin-test/sources/esm',
+          expected: BASE_STACK,
+        },
+        {
+          name: 'with main',
+
+          modulePath: './scripts/bin-test/sources/esm-main',
+          expected: BASE_STACK,
+        },
+        {
+          name: 'with .m extension',
+          modulePath: './scripts/bin-test/sources/esm-ext',
+          expected: BASE_STACK,
+        },
+      ];
+
+      for (const tc of testcases) {
+        describe(tc.name, async () => {
+          await runTests(tc);
+        });
+      }
+    }).timeout(TIMEOUT_L);
+  }
+}).timeout(TIMEOUT_XL);
diff --git a/scripts/publish.sh b/scripts/publish.sh
index ea5acde68..a7574a15a 100644
--- a/scripts/publish.sh
+++ b/scripts/publish.sh
@@ -80,6 +80,7 @@ echo "Ran npm ci."
 
 echo "Running tests..."
 npm test
+npm run test:bin
 echo "Ran tests."
 
 echo "Running publish build..."
diff --git a/spec/runtime/loader.spec.ts b/spec/runtime/loader.spec.ts
index 1dab77c43..436d3ea62 100644
--- a/spec/runtime/loader.spec.ts
+++ b/spec/runtime/loader.spec.ts
@@ -1,5 +1,4 @@
 import * as path from 'path';
-import * as semver from 'semver';
 import { expect } from 'chai';
 
 import * as loader from '../../src/runtime/loader';
@@ -251,13 +250,13 @@ describe('loadStack', () => {
     expected: ManifestStack;
   };
   function runTests(tc: Testcase) {
-    it('loads backend given relative path', async () => {
+    it('loads stack given relative path', async () => {
       await expect(loader.loadStack(tc.modulePath)).to.eventually.deep.equal(
         tc.expected
       );
     });
 
-    it('loads backend given absolute path', async () => {
+    it('loads stack given absolute path', async () => {
       await expect(
         loader.loadStack(path.join(process.cwd(), tc.modulePath))
       ).to.eventually.deep.equal(tc.expected);
@@ -317,32 +316,4 @@ describe('loadStack', () => {
       });
     }
   });
-
-  if (semver.gt(process.versions.node, '13.2.0')) {
-    describe('esm', () => {
-      const testcases: Testcase[] = [
-        {
-          name: 'basic',
-          modulePath: './spec/fixtures/sources/esm',
-          expected,
-        },
-        {
-          name: 'with main',
-          modulePath: './spec/fixtures/sources/esm-main',
-          expected,
-        },
-        {
-          name: 'with .m extension',
-          modulePath: './spec/fixtures/sources/esm-ext',
-          expected,
-        },
-      ];
-
-      for (const tc of testcases) {
-        describe(tc.name, () => {
-          runTests(tc);
-        });
-      }
-    });
-  }
 });