diff --git a/package.json b/package.json
index 699184cf2cd..6d71537ae53 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
     "typescript-eslint": "^8.66.0"
   },
   "scripts": {
-    "test": "npx nx run-many -t test --exclude=blockly && npx nx run blockly:test",
+    "test": "npx nx run-many -t test",
     "lint": "npm run lint --ws --if-present",
     "lint-fix": "npm run lint-fix --ws --if-present",
     "build": "npx nx run-many -t build --exclude=blockly-docs",
diff --git a/packages/blockly/gulpfile.mjs b/packages/blockly/gulpfile.mjs
index 82b393382ef..d68143d2d7c 100644
--- a/packages/blockly/gulpfile.mjs
+++ b/packages/blockly/gulpfile.mjs
@@ -36,7 +36,6 @@ import {
   pack,
   typings,
 } from './scripts/gulpfiles/package_tasks.mjs';
-import {generators, test} from './scripts/gulpfiles/test_tasks.mjs';
 
 const clean = parallel(cleanBuildDir, cleanReleaseDir);
 
@@ -66,8 +65,6 @@ export {
 export {
   messages, // Generate msg/json/en.json et al.
   clean,
-  test,
-  generators as testGenerators,
   buildAdvancedCompilationTest,
   typings,
 }
diff --git a/packages/blockly/package.json b/packages/blockly/package.json
index ef69695c10b..df156c62aa8 100644
--- a/packages/blockly/package.json
+++ b/packages/blockly/package.json
@@ -51,6 +51,10 @@
       },
       "test": {
         "dependsOn": [
+          {
+            "projects": "blockly",
+            "target": "package"
+          },
           {
             "projects": "@blockly/block-test",
             "target": "build"
@@ -61,6 +65,14 @@
           }
         ]
       },
+      "test-compile-advanced-browser": {
+        "dependsOn": [
+          {
+            "projects": "blockly",
+            "target": "test-compile-advanced"
+          }
+        ]
+      },
       "docs": {
         "dependsOn": [
           "package",
@@ -101,13 +113,16 @@
     "rebuildAdvancedPlayground": "npm run build --workspace=@blockly/dev-tools && node \"scripts/prepare_advanced_playground.mjs\"",
     "rebuildBlockly": "npm run build && node \"scripts/prepare_advanced_playground.mjs\"",
     "tsc": "gulp tsc",
-    "test": "gulp test",
+    "test": "nx run-many -p blockly --targets=lint,test-renamings,test-mocha-node,test-generators,test-type-definitions,test-compile-advanced,test-compile-advanced-browser",
     "test-browser": "npx mocha --config tests/browser/.mocharc.js",
     "test-mocha-node": "npm run test-mocha-typecheck && npx mocha --config tests/mocha/.mocharc.node.cjs \"tests/mocha/**/*_test.{js,ts}\"",
     "test-mocha-typecheck": "tsc -p tests/mocha/tsconfig.json",
-    "test-generators": "gulp testGenerators",
+    "test-generators": "node \"tests/generators/test_generators.mjs\"",
     "test-mocha-interactive": "npm run build && node scripts/prepare_mocha_bundle.mjs && concurrently -n tsc,tsc:tests,esbuild,python3 \"tsc --watch --preserveWatchOutput --outDir \"build/src\" --declarationDir \"build/declarations\"\" \"npm run test-mocha-typecheck -- --watch --preserveWatchOutput\" \"esbuild build/tests/bundle-entry.js --bundle --sourcemap --alias:blockly/core=./build/src/core/blockly.js --alias:blockly/blocks=./build/src/blocks/blocks.js --alias:blockly=./build/src/core/blockly.js --outfile=build/tests/mocha-bundle.js --servedir=. --serve=127.0.0.1:8080 --watch=forever --log-level=warning\" \"python3 -m webbrowser 'http://localhost:8080/tests/mocha/index.html'\"",
     "test-compile-advanced": "gulp buildAdvancedCompilationTest --debug",
+    "test-compile-advanced-browser": "node \"tests/compile/webdriver.js\"",
+    "test-renamings": "node \"tests/migration/validate-renamings.mjs\"",
+    "test-type-definitions": "tsc -p ./tests/typescript/tsconfig.json -outDir \"build/src\"",
     "updateGithubPages": "node scripts/update_github_pages.mjs --upstream",
     "updateGithubPages-staging": "node scripts/update_github_pages.mjs --use-local"
   },
diff --git a/packages/blockly/scripts/gulpfiles/test_tasks.mjs b/packages/blockly/scripts/gulpfiles/test_tasks.mjs
deleted file mode 100644
index 031f43482c0..00000000000
--- a/packages/blockly/scripts/gulpfiles/test_tasks.mjs
+++ /dev/null
@@ -1,305 +0,0 @@
-/**
- * @license
- * Copyright 2022 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * @fileoverview Gulp tasks to test.
- */
-/* eslint-env node */
-
-import asyncDone from 'async-done';
-import {spawnSync} from 'child_process';
-import * as fs from 'fs';
-import * as gulp from 'gulp';
-import * as path from 'path';
-import {rimraf} from 'rimraf';
-
-import {TEST_TSC_OUTPUT_DIR} from './config.mjs';
-
-const OUTPUT_DIR = 'build/generators';
-const GOLDEN_DIR = 'tests/generators/golden';
-
-const BOLD_GREEN = '\x1b[1;32m';
-const BOLD_RED = '\x1b[1;31m';
-const ANSI_RESET = '\x1b[0m';
-
-let successCount = 0;
-let failCount = 0;
-let firstErr;
-const results = {};
-
-/**
- * Run an arbitrary Gulp task as a test.
- * @param {function} task Any Gulp task.
- * @return {Promise} Asynchronous result.
- */
-function runTestTask(id, task) {
-  return new Promise((resolve) => {
-    console.log('=======================================');
-    console.log(`== ${id}`);
-
-    // Turn any task into a Promise!
-    const asyncTask = new Promise((resolve, reject) => {
-      asyncDone(task, (error, result) => {
-        if (error) reject(error);
-        resolve(result);
-      });
-    });
-
-    if (process.env.CI) console.log('::group::');
-    asyncTask
-      .then((result) => {
-        successCount++;
-        if (process.env.CI) console.log('::endgroup::');
-        console.log(`${BOLD_GREEN}SUCCESS:${ANSI_RESET} ${id}`);
-        results[id] = {success: true};
-        resolve(result);
-      })
-      .catch((err) => {
-        failCount++;
-        if (!firstErr) {
-          // Save the first error so we can use it in the stack trace later.
-          firstErr = err;
-        }
-        console.error(err.message);
-        if (process.env.CI) console.log('::endgroup::');
-        console.log(`${BOLD_RED}FAILED:${ANSI_RESET} ${id}`);
-        results[id] = {success: false, message: err.message};
-        // Always continue.
-        resolve(err);
-      });
-  });
-}
-
-function createSummary() {
-  let summary = '# Test Summary\n\n';
-  summary += '|Test Name|Passed?|Error message|\n';
-  summary += '|---------|-------|-------------|\n';
-  for (const test in results) {
-    summary += `|${test}|${results[test].success
-      ? ':white_check_mark:' : ':x:'}|${results[test].message ?? ''}|\n`;
-  }
-  summary += `\n\n## Total: ${successCount} passed. ${failCount} failed.`;
-  return summary;
-}
-
-/**
- * Print test results and fail the task if needed.
- */
-function reportTestResult() {
-  console.log('=======================================');
-  if (process.env.CI && process.env.GITHUB_STEP_SUMMARY) {
-    try {
-      fs.writeFileSync(process.env.GITHUB_STEP_SUMMARY, createSummary());
-    } catch(e) {
-      // Don't fail CI just because we couldn't write the summary.
-      console.log('Failed to write job summary', e);
-    }
-  }
-  // Check result.
-  if (failCount === 0) {
-    console.log(
-        `${BOLD_GREEN}All ${successCount} tests passed.${ANSI_RESET}`);
-    return Promise.resolve();
-  }
-  console.log(
-      `${BOLD_RED}Failures in ${failCount} test groups.${ANSI_RESET}`);
-  return Promise.reject(firstErr ||
-      'Unspecified test failures, see above. The following stack trace is unlikely to be useful.');
-}
-
-/**
- * Helper method for running test command.
- * @param {string} command Command line to run.
- * @return {Promise} Asynchronous result.
- */
-async function runTestCommand(id, command) {
-  return runTestTask(id, async () => {
-    const result = spawnSync(command, {
-      shell: true,
-      stdio: 'inherit',
-      env: process.env,
-    });
-    if (result.error) {
-      throw result.error;
-    }
-    if (result.status !== 0) {
-      throw new Error(
-          `Command failed with exit code ${result.status}: ${command}`,
-      );
-    }
-  });
-}
-
-/**
- * Lint the codebase.
- * Skip for CI environments, because linting is run separately.
- * @return {Promise} Asynchronous result.
- */
-function eslint() {
-  if (process.env.CI) {
-    console.log('Skip linting.');
-    return Promise.resolve();
-  }
-  return runTestCommand('eslint', 'eslint .');
-}
-
-/**
- * Run the full usual build and package process, checking to ensure
- * there are no Closure Compiler warnings / errors.
- * @return {Promise} Asynchronous result.
- */
-function build() {
-  return runTestCommand('build', 'npm run package -- --verbose --debug');
-}
-
-/**
- * Run renaming validation test.
- * @return {Promise} Asynchronous result.
- */
-function renamings() {
-  return runTestCommand('renamings', 'tests/migration/validate-renamings.mjs');
-}
-
-/**
- * Run Mocha tests under Node.
- * @return {Promise} Asynchronous result.
- */
-function mocha() {
-  return runTestCommand('mocha', 'npm run test-mocha-node');
-}
-
-/**
- * Helper method for comparison file.
- * @param {string} file1 First target file.
- * @param {string} file2 Second target file.
- * @return {boolean} Comparison result (true: same / false: different).
- */
-function compareFile(file1, file2) {
-  const buf1 = fs.readFileSync(file1);
-  const buf2 = fs.readFileSync(file2);
-  // Normalize the line feed.
-  const code1 = buf1.toString().replace(/(?:\r\n|\r|\n)/g, '\n');
-  const code2 = buf2.toString().replace(/(?:\r\n|\r|\n)/g, '\n');
-  return code1 === code2;
-}
-
-/**
- * Helper method for checking the result of generator.
- * @param {string} suffix Target suffix.
- * @return {number} Check result (0: success / 1: failed).
- */
-function checkResult(suffix) {
-  const fileName = `generated.${suffix}`;
-  const resultFileName = path.posix.join(OUTPUT_DIR, fileName);
-
-  const SUCCESS_PREFIX = `${BOLD_GREEN}SUCCESS:${ANSI_RESET}`;
-  const FAILURE_PREFIX = `${BOLD_RED}FAILED:${ANSI_RESET}`;
-
-  if (fs.existsSync(resultFileName)) {
-    const goldenFileName = path.posix.join(GOLDEN_DIR, fileName);
-    if (fs.existsSync(goldenFileName)) {
-      if (compareFile(resultFileName, goldenFileName)) {
-        console.log(`${SUCCESS_PREFIX} ${suffix}: ` +
-            `${resultFileName} matches ${goldenFileName}`);
-        return 0;
-      } else {
-        console.log(
-            `${FAILURE_PREFIX} ${suffix}: ` +
-            `${resultFileName} does not match ${goldenFileName}`);
-      }
-    } else {
-      console.log(`File ${goldenFileName} not found!`);
-    }
-  } else {
-    console.log(`File ${resultFileName} not found!`);
-  }
-  return 1;
-}
-
-/**
- * Run generator tests inside a browser and check the results.
- * @return {Promise} Asynchronous result.
- */
-export async function generators() {
-  return runTestTask('generators', async () => {
-    // Clean up.
-    rimraf.sync(OUTPUT_DIR);
-    fs.mkdirSync(OUTPUT_DIR);
-
-    const result = spawnSync('node', ['tests/generators/webdriver.js', OUTPUT_DIR], {
-      stdio: 'inherit',
-      env: process.env,
-    });
-    if (result.error) {
-      throw result.error;
-    }
-    if (result.status !== 0) {
-      throw new Error('Generator browser tests failed.');
-    }
-
-    const generatorSuffixes = ['js', 'py', 'dart', 'lua', 'php'];
-    let failed = 0;
-    generatorSuffixes.forEach((suffix) => {
-      failed += checkResult(suffix);
-    });
-
-    if (failed === 0) {
-      console.log(`${BOLD_GREEN}All generator tests passed.${ANSI_RESET}`);
-    } else {
-      console.log(
-          `${BOLD_RED}Failures in ${failed} generator tests.${ANSI_RESET}`);
-      throw new Error('Generator tests failed.');
-    }
-  });
-}
-
-/**
- * Attempt advanced compilation of a Blockly app.
- * @returns {Promise} Async result.
- */
-function advancedCompile() {
-  return runTestCommand('advanced_compile', 'npm run test-compile-advanced');
-}
-
-/**
- * Attempt advanced compilation of a Blockly app and make sure it runs in the browser.
- * Should be run after the `advancedCompile` test.
- * @return {Promise} Asynchronous result.
- */
-function advancedCompileInBrowser() {
-  return runTestCommand(
-      'advanced_compile_in_browser',
-      'node tests/compile/webdriver.js',
-  );
-}
-
-/**
- * Verify the built Blockly type definitions compile with the supported
- * TypeScript examples included in `./tests/typescript`.
- * @returns {Promise} Asynchronous result.
- */
-function typeDefinitions() {
-  return runTestCommand('type_definitions',
-    `tsc -p ./tests/typescript/tsconfig.json -outDir ${TEST_TSC_OUTPUT_DIR}`);
-}
-
-// Run all tests in sequence.
-const tasks = [
-  eslint,
-  // Build must run before the remaining tasks
-  build,
-  renamings,
-  mocha,
-  generators,
-  typeDefinitions,
-  // Make sure these two are in series with each other
-  advancedCompile,
-  advancedCompileInBrowser
-];
-
-export const test = gulp.series(...tasks, reportTestResult);
-
-
diff --git a/packages/blockly/tests/generators/test_generators.mjs b/packages/blockly/tests/generators/test_generators.mjs
new file mode 100644
index 00000000000..8395d3d5c17
--- /dev/null
+++ b/packages/blockly/tests/generators/test_generators.mjs
@@ -0,0 +1,119 @@
+/**
+ * @license
+ * Copyright 2026 Raspberry Pi Foundation
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Tests the Blockly generators inside a browser and reports the
+ * results.
+ */
+
+import {spawnSync} from 'child_process';
+import * as fs from 'fs';
+import * as path from 'path';
+import {rimraf} from 'rimraf';
+import {
+  ANSI_RESET,
+  BOLD_GREEN,
+  BOLD_RED,
+  runTestFunction,
+} from '../scripts/test_helpers.mjs';
+
+export const OUTPUT_DIR = 'build/generators';
+export const GOLDEN_DIR = 'tests/generators/golden';
+
+/**
+ * Helper method for checking the result of generator.
+ * @param {string} suffix Target suffix.
+ * @return {number} Check result (0: success / 1: failed).
+ */
+export function checkResult(suffix) {
+  const fileName = `generated.${suffix}`;
+  const resultFileName = path.posix.join(OUTPUT_DIR, fileName);
+
+  const SUCCESS_PREFIX = `${BOLD_GREEN}SUCCESS:${ANSI_RESET}`;
+  const FAILURE_PREFIX = `${BOLD_RED}FAILED:${ANSI_RESET}`;
+
+  if (fs.existsSync(resultFileName)) {
+    const goldenFileName = path.posix.join(GOLDEN_DIR, fileName);
+    if (fs.existsSync(goldenFileName)) {
+      if (compareFile(resultFileName, goldenFileName)) {
+        console.log(
+          `${SUCCESS_PREFIX} ${suffix}: ` +
+            `${resultFileName} matches ${goldenFileName}`,
+        );
+        return 0;
+      } else {
+        console.log(
+          `${FAILURE_PREFIX} ${suffix}: ` +
+            `${resultFileName} does not match ${goldenFileName}`,
+        );
+      }
+    } else {
+      console.log(`File ${goldenFileName} not found!`);
+    }
+  } else {
+    console.log(`File ${resultFileName} not found!`);
+  }
+  return 1;
+}
+
+/**
+ * Helper method for comparison file.
+ * @param {string} file1 First target file.
+ * @param {string} file2 Second target file.
+ * @return {boolean} Comparison result (true: same / false: different).
+ */
+function compareFile(file1, file2) {
+  const buf1 = fs.readFileSync(file1);
+  const buf2 = fs.readFileSync(file2);
+  // Normalize the line feed.
+  const code1 = buf1.toString().replace(/(?:\r\n|\r|\n)/g, '\n');
+  const code2 = buf2.toString().replace(/(?:\r\n|\r|\n)/g, '\n');
+  return code1 === code2;
+}
+
+/**
+ * Run generator tests inside a browser and check the results.
+ * @return {Promise} Asynchronous result.
+ */
+export async function generators() {
+  return runTestFunction('generators', async () => {
+    // Clean up.
+    rimraf.sync(OUTPUT_DIR);
+    fs.mkdirSync(OUTPUT_DIR);
+
+    const result = spawnSync(
+      'node',
+      ['tests/generators/webdriver.js', OUTPUT_DIR],
+      {
+        stdio: 'inherit',
+        env: process.env,
+      },
+    );
+    if (result.error) {
+      throw result.error;
+    }
+    if (result.status !== 0) {
+      throw new Error('Generator browser tests failed.');
+    }
+
+    const generatorSuffixes = ['js', 'py', 'dart', 'lua', 'php'];
+    let failed = 0;
+    generatorSuffixes.forEach((suffix) => {
+      failed += checkResult(suffix);
+    });
+
+    if (failed === 0) {
+      console.log(`${BOLD_GREEN}All generator tests passed.${ANSI_RESET}`);
+    } else {
+      console.log(
+        `${BOLD_RED}Failures in ${failed} generator tests.${ANSI_RESET}`,
+      );
+      throw new Error('Generator tests failed.');
+    }
+  });
+}
+
+await generators();
diff --git a/packages/blockly/tests/scripts/test_helpers.mjs b/packages/blockly/tests/scripts/test_helpers.mjs
new file mode 100644
index 00000000000..e49d63698aa
--- /dev/null
+++ b/packages/blockly/tests/scripts/test_helpers.mjs
@@ -0,0 +1,75 @@
+/**
+ * @license
+ * Copyright 2022 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Node test scripts.
+ */
+import asyncDone from 'async-done';
+import {spawnSync} from 'child_process';
+
+export const BOLD_GREEN = '\x1b[1;32m';
+export const BOLD_RED = '\x1b[1;31m';
+export const ANSI_RESET = '\x1b[0m';
+
+/**
+ * Run an arbitrary function as a test.
+ * @param {id} id The test id/name.
+ * @param {function(): Promise} testFunction Any function to be run as a test.
+ * @return {Promise} Asynchronous result.
+ */
+export function runTestFunction(id, testFunction) {
+  return new Promise((resolve) => {
+    console.log('=======================================');
+    console.log(`== ${id}`);
+
+    // Turn the testFunction into a Promise
+    const asyncFunction = new Promise((resolve, reject) => {
+      asyncDone(testFunction, (error, result) => {
+        if (error) reject(error);
+        resolve(result);
+      });
+    });
+
+    if (process.env.CI) console.log('::group::');
+    asyncFunction
+      .then((result) => {
+        if (process.env.CI) console.log('::endgroup::');
+        console.log(`${BOLD_GREEN}SUCCESS:${ANSI_RESET} ${id}`);
+        resolve(result);
+      })
+      .catch((err) => {
+        console.error(err.message);
+        if (process.env.CI) console.log('::endgroup::');
+        console.log(`${BOLD_RED}FAILED:${ANSI_RESET} ${id}`);
+        // Always continue.
+        resolve(err);
+      });
+  });
+}
+
+/**
+ * Helper method for running test command.
+ * @param {id} id The test command id/name.
+ * @param {string} command Command line to run.
+ * @return {Promise} Asynchronous result.
+ */
+export async function runTestCommand(id, command) {
+  return runTestFunction(id, async () => {
+    const result = spawnSync(command, {
+      shell: true,
+      stdio: 'inherit',
+      env: process.env,
+    });
+    if (result.error) {
+      throw result.error;
+    }
+    if (result.status !== 0) {
+      throw new Error(
+        `Command failed with exit code ${result.status}: ${command}`,
+      );
+    }
+  });
+}