diff --git a/.github/workflows/cross-browser-test.yml b/.github/workflows/cross-browser-test.yml
index 3f01ec436d5..8f9eb6a9db3 100644
--- a/.github/workflows/cross-browser-test.yml
+++ b/.github/workflows/cross-browser-test.yml
@@ -1,11 +1,17 @@
 name: Cross-Browser Test Flow
 
-on: push
+on:
+  pull_request:
+    branches:
+      - master
+    types:
+      - closed
 
 jobs:
   cross-browser-test:
     name: Cross-Browser (Saucelabs) Tests
     runs-on: ubuntu-latest
+    if: github.event.pull_request.merged
     env:
       SAUCE_ACCESS_KEY: ${{ secrets.SAUCE_ACCESS_KEY }}
       SAUCE_USERNAME: ${{ secrets.SAUCE_USERNAME }}
diff --git a/.github/workflows/node-chrome-test.yml b/.github/workflows/test-all.yml
similarity index 84%
rename from .github/workflows/node-chrome-test.yml
rename to .github/workflows/test-all.yml
index a7832c1c2ff..50c654444cc 100644
--- a/.github/workflows/node-chrome-test.yml
+++ b/.github/workflows/test-all.yml
@@ -1,6 +1,13 @@
-name: Main Test Flow
+name: Run All Tests
 
-on: [push, pull_request]
+on:
+  pull_request:
+    branches:
+      - master
+    types:
+      - closed
+  schedule:
+    - cron: '0 6,18 * * *'
 
 jobs:
   test:
diff --git a/.github/workflows/test-changed.yml b/.github/workflows/test-changed.yml
new file mode 100644
index 00000000000..94458506548
--- /dev/null
+++ b/.github/workflows/test-changed.yml
@@ -0,0 +1,23 @@
+name: Push/PR
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: Test Packages With Changed Files
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+    - name: Set up Node (10)
+      uses: actions/setup-node@v1
+      with:
+        node-version: 10.x
+    - name: Test setup and yarn install
+      run: |
+        cp config/ci.config.json config/project.json
+        yarn
+    - name: yarn build
+      run: yarn build
+    - name: Run tests on changed packages
+      run: xvfb-run yarn test:changed
diff --git a/package.json b/package.json
index 549201e9f83..3c6f9ca4cd6 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
     "pretest:coverage": "mkdirp coverage",
     "ci:coverage": "lcov-result-merger 'packages/**/lcov.info' 'lcov-all.info'",
     "test:coverage": "lcov-result-merger 'packages/**/lcov.info' | coveralls",
+    "test:changed": "node scripts/run_changed.js",
     "test:setup": "node tools/config.js",
     "test:saucelabs": "node scripts/run_saucelabs.js",
     "test:saucelabs:single": "karma start config/karma.saucelabs.js --single-run",
diff --git a/scripts/run_changed.js b/scripts/run_changed.js
new file mode 100644
index 00000000000..19233cec97d
--- /dev/null
+++ b/scripts/run_changed.js
@@ -0,0 +1,89 @@
+/**
+ * @license
+ * Copyright 2020 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const { resolve } = require('path');
+const { spawn } = require('child-process-promise');
+const simpleGit = require('simple-git/promise');
+const root = resolve(__dirname, '..');
+const git = simpleGit(root);
+
+/**
+ * Runs tests on packages changed (in comparison to origin/master...HEAD)
+ */
+
+async function runTestsOnChangedPackages() {
+  const diff = await git.diff(['--name-only', 'origin/master...HEAD']);
+  const changedFiles = diff.split('\n');
+  const changedPackages = {};
+  for (const filename of changedFiles) {
+    const match = filename.match('^(packages/[a-zA-Z0-9-]+)/.*');
+    if (match && match[1]) {
+      const pkg = require(resolve(root, match[1], 'package.json'));
+      if (pkg && pkg.scripts.test) {
+        changedPackages[match[1]] = true;
+      }
+    }
+  }
+  if (changedPackages.size > 0) {
+    await runTests(Object.keys(changedPackages));
+  } else {
+    console.log(
+      'No changes detected in any package. Skipping all package-specific tests.'
+    );
+  }
+}
+
+/**
+ * Runs `yarn test` in all dirs in pathList.
+ * @param {Array<string>} pathList
+ */
+async function runTests(pathList) {
+  if (!pathList) return;
+  for (const testPath of pathList) {
+    try {
+      await spawn('yarn', ['--cwd', testPath, 'test'], {
+        stdio: 'inherit'
+      });
+    } catch (e) {
+      throw new Error(`Error running tests in ${testPath}.`);
+    }
+  }
+}
+
+/**
+ * These are short, always run them.
+ */
+async function runIntegrationTests() {
+  await runTests([
+    'integration/browserify',
+    'integration/firebase-typings',
+    'integration/typescript',
+    'integration/webpack'
+  ]);
+}
+
+async function main() {
+  try {
+    await runIntegrationTests();
+    await runTestsOnChangedPackages();
+  } catch (e) {
+    console.error(e);
+    process.exit(1);
+  }
+}
+
+main();
diff --git a/tools/gitHooks/license.js b/tools/gitHooks/license.js
index 4bc64e01983..8f2c0fcdc44 100644
--- a/tools/gitHooks/license.js
+++ b/tools/gitHooks/license.js
@@ -11,7 +11,7 @@ const root = resolve(__dirname, '../..');
 const git = simpleGit(root);
 const licenseHeader = `/**
  * @license
- * Copyright 2019 Google Inc.
+ * Copyright 2020 Google Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.