diff --git a/src/Console/bin/bones b/src/Console/bin/bones
index a0dd969..152c036 100644
--- a/src/Console/bin/bones
+++ b/src/Console/bin/bones
@@ -1675,6 +1675,46 @@ namespace Bones {
       return $other ? $stubs : ['/' . self::PLUGIN_STUBS];
     }
 
+    /**
+     * The JavaScript tests that sit beside the code they test, found the way the jest.config.js
+     * written by `migrate:to-v2` finds them: every `__tests__` folder, and every `*.test.*` or
+     * `*.spec.*` script, with the `__snapshots__` and `__mocks__` folders Jest keeps beside them.
+     * They live in resources/assets, which `--wp` ships. The skip list matches exact paths, so
+     * each one is listed where it is.
+     *
+     * vendor/ and node_modules/ are not walked: they are not the plugin's own code. Neither is a
+     * folder that cannot be read, which the copy could not read either.
+     *
+     * @since 3.2.0
+     * @param string $relative The folder to walk, relative to the plugin root.
+     * @return string[] Entries of the deploy skip list.
+     */
+    protected function javascriptTestsToSkip(string $relative = ''): array
+    {
+      $entries = [];
+
+      foreach (scandir(__DIR__ . $relative) ?: [] as $name) {
+        // The deploy never copies a dot entry, so there is nothing to list in one.
+        if (strpos($name, '.') === 0 || in_array($name, ['vendor', 'node_modules'], true)) {
+          continue;
+        }
+
+        $path = "{$relative}/{$name}";
+
+        if (is_dir(__DIR__ . $path)) {
+          if (in_array($name, ['__tests__', '__snapshots__', '__mocks__'], true)) {
+            $entries[] = $path;
+          } elseif (!is_link(__DIR__ . $path) && is_readable(__DIR__ . $path)) {
+            $entries = array_merge($entries, $this->javascriptTestsToSkip($path));
+          }
+        } elseif (preg_match('/\.(test|spec)\.(ts|tsx|js|jsx)$/', $name)) {
+          $entries[] = $path;
+        }
+      }
+
+      return $entries;
+    }
+
     /**
      * Return true if the command is available in the system.
      *
@@ -2719,6 +2759,14 @@ namespace Bones {
         '/phpcs.xml.dist',
         '/mix-manifest.json',
         '/release.sh',
+        // The plugin's test suites: PHPUnit's, where PHPUnit looks for it, and Jest's.
+        '/tests',
+        '/phpunit.xml',
+        '/phpunit.xml.dist',
+        '/phpunit.dist.xml',
+        '/jest.config.js',
+        '/jest.config.json',
+        ...$this->javascriptTestsToSkip(),
         ...$this->pluginStubsToSkip(),
       ]);
 
@@ -2759,6 +2807,8 @@ namespace Bones {
         $this->pruneDevPackages($path);
       }
 
+      $this->assertAutoloadedFilesShipped($path, $is_create_zip);
+
       /**
        * Fires when the console deploy is completed.
        *
@@ -3110,6 +3160,47 @@ namespace Bones {
       }
     }
 
+    /**
+     * Stop when the package's Composer autoloader requires a file the package does not hold.
+     *
+     * Composer requires its `files` entries on every request, so one that points at a path the
+     * deploy left out is a fatal error the moment the plugin loads. It happens when autoload-dev
+     * names a file in `tests/` and the dev autoloader stays: with --keep-dev, or when no dev
+     * package is installed and so none is pruned and the autoloader is not rebuilt.
+     *
+     * @since 3.2.0
+     * @param string $path The deployed copy.
+     * @param bool $isTemporary True when the copy is the folder a zip is made from.
+     */
+    protected function assertAutoloadedFilesShipped(string $path, bool $isTemporary): void
+    {
+      $map = "{$path}/vendor/composer/autoload_files.php";
+
+      if (!is_file($map)) {
+        return;
+      }
+
+      // The map works out its paths from where it sits, so in the copy they point into the copy.
+      $files = (static fn() => require $map)();
+      $missing = array_filter(is_array($files) ? $files : [], fn($file) => !is_file($file));
+
+      if (empty($missing)) {
+        return;
+      }
+
+      $root = (realpath($path) ?: $path) . '/';
+      $list = implode(', ', array_map(fn($file) => str_replace($root, '', $file), $missing));
+
+      if ($isTemporary) {
+        $this->deleteDirectory($path);
+      }
+
+      $this->error(
+        "The package's Composer autoloader requires files the deploy left out ({$list}), so the plugin would stop with a fatal error as it loads. Move them out of composer.json's autoload-dev, or keep them in the package with the wpbones_console_deploy_default_skip_files_folders filter.",
+      );
+      exit(1);
+    }
+
     /**
      * The command that runs Composer: a composer.phar in the plugin root, else `composer` on PATH.
      */
diff --git a/tests/Console/DeployTestSuitesTest.php b/tests/Console/DeployTestSuitesTest.php
new file mode 100644
index 0000000..1308a31
--- /dev/null
+++ b/tests/Console/DeployTestSuitesTest.php
@@ -0,0 +1,165 @@
+<?php
+
+declare(strict_types=1);
+
+namespace WPKirk\WPBones\Tests\Console;
+
+use PHPUnit\Framework\Attributes\Group;
+use PHPUnit\Framework\TestCase;
+use WPKirk\WPBones\Tests\Support\BonesProcess;
+
+/**
+ * A plugin's own test suites shipped with every deploy unless its deploy.php listed them: the
+ * default skip list named no `tests/`, no PHPUnit or Jest configuration, and no Jest test, and
+ * since `--wp` keeps `resources/assets`, every `__tests__` folder beside the scripts it tests
+ * went to WordPress.org with them. Scotty 2.2.0 shipped four, removed by hand before the SVN
+ * commit.
+ *
+ * Since 3.2.0 the deploy leaves out the PHP suite where PHPUnit looks for it, and the JavaScript
+ * tests where the jest.config.js that `migrate:to-v2` writes looks for them.
+ */
+#[Group('console')]
+final class DeployTestSuitesTest extends TestCase
+{
+  private BonesProcess $bones;
+
+  private string $target = '';
+
+  protected function setUp(): void
+  {
+    parent::setUp();
+
+    $this->bones = new BonesProcess();
+    $this->target = $this->bones->root . '/out';
+
+    foreach (
+      [
+        'plugin/Http/Controllers/TestController.php' => "<?php\n// runtime code\n",
+        'tests/bootstrap.php' => "<?php\n",
+        'tests/Unit/ExampleTest.php' => "<?php\n",
+        'phpunit.xml' => "<phpunit/>\n",
+        'phpunit.xml.dist' => "<phpunit/>\n",
+        'phpunit.dist.xml' => "<phpunit/>\n",
+        'jest.config.js' => "module.exports = {};\n",
+        'jest.config.json' => "{}\n",
+        'resources/assets/apps/components/Header.tsx' => "export {};\n",
+        'resources/assets/apps/components/__tests__/Header.test.tsx' => "test('x', () => {});\n",
+        'resources/assets/apps/components/__tests__/fixtures/data.json' => "{}\n",
+        'resources/assets/apps/utils/format.ts' => "export {};\n",
+        'resources/assets/apps/utils/format.test.ts' => "test('x', () => {});\n",
+        'resources/assets/apps/utils/format.spec.js' => "test('x', () => {});\n",
+        'resources/assets/apps/utils/latest.ts' => "export {};\n",
+        'resources/assets/apps/utils/__snapshots__/format.test.ts.snap' => "// snapshot\n",
+        'resources/assets/apps/utils/__mocks__/api.ts' => "export {};\n",
+        '__mocks__/fs.js' => "module.exports = {};\n",
+        'vendor/acme/lib/__tests__/lib.test.js' => "test('x', () => {});\n",
+        'vendor/acme/lib/functions.php' => "<?php\n",
+        // Composer's map of the files it requires on every request; $vendorDir and $baseDir are
+        // where the copy sits, as in the real one.
+        'vendor/composer/autoload_files.php' => "<?php\n\$vendorDir = dirname(__DIR__);\n\$baseDir = dirname(\$vendorDir);\n\nreturn array(\n  'a1' => \$vendorDir . '/acme/lib/functions.php',\n);\n",
+      ]
+      as $file => $content
+    ) {
+      $path = $this->bones->plugin . '/' . $file;
+
+      if (!is_dir(dirname($path))) {
+        mkdir(dirname($path), 0777, true);
+      }
+
+      file_put_contents($path, $content);
+    }
+  }
+
+  protected function tearDown(): void
+  {
+    $this->bones->remove();
+
+    parent::tearDown();
+  }
+
+  /** @return array{status:int, output:string} */
+  private function deploy(string ...$options): array
+  {
+    return $this->bones->run(['deploy', $this->target, '--no-build', ...$options]);
+  }
+
+  public function test_the_php_suite_does_not_reach_the_package(): void
+  {
+    $result = $this->deploy();
+
+    $this->assertSame(0, $result['status'], $result['output']);
+    $this->assertFileExists($this->target . '/wp-kirk.php', 'the deploy did not run');
+    $this->assertDirectoryDoesNotExist($this->target . '/tests');
+    $this->assertFileDoesNotExist($this->target . '/phpunit.xml');
+    $this->assertFileDoesNotExist($this->target . '/phpunit.xml.dist');
+    $this->assertFileDoesNotExist($this->target . '/phpunit.dist.xml');
+  }
+
+  public function test_the_javascript_tests_do_not_reach_a_wordpress_org_package(): void
+  {
+    $result = $this->deploy('--wp');
+    $assets = $this->target . '/resources/assets/apps';
+
+    $this->assertSame(0, $result['status'], $result['output']);
+    $this->assertFileExists($assets . '/components/Header.tsx', '--wp did not keep resources/assets');
+    $this->assertFileDoesNotExist($this->target . '/jest.config.js');
+    $this->assertFileDoesNotExist($this->target . '/jest.config.json');
+    $this->assertDirectoryDoesNotExist($assets . '/components/__tests__');
+    $this->assertFileDoesNotExist($assets . '/utils/format.test.ts');
+    $this->assertFileDoesNotExist($assets . '/utils/format.spec.js');
+    $this->assertDirectoryDoesNotExist($assets . '/utils/__snapshots__');
+    $this->assertDirectoryDoesNotExist($assets . '/utils/__mocks__');
+    $this->assertDirectoryDoesNotExist($this->target . '/__mocks__');
+  }
+
+  public function test_an_autoloaded_file_the_deploy_left_out_stops_it(): void
+  {
+    // autoload-dev "files" pointing into tests/: the dev autoloader stays when nothing is pruned
+    // (no dev package installed, as here, or --keep-dev), and it would require a missing file
+    // on every request.
+    file_put_contents($this->bones->plugin . '/tests/helpers.php', "<?php\n");
+    file_put_contents(
+      $this->bones->plugin . '/vendor/composer/autoload_files.php',
+      "<?php\n\$vendorDir = dirname(__DIR__);\n\$baseDir = dirname(\$vendorDir);\n\nreturn array(\n  'a1' => \$vendorDir . '/acme/lib/functions.php',\n  'b2' => \$baseDir . '/tests/helpers.php',\n);\n"
+    );
+
+    $result = $this->deploy();
+
+    $this->assertNotSame(0, $result['status'], 'a package that cannot load was reported as deployed');
+    $this->assertStringContainsString('tests/helpers.php', $result['output']);
+    $this->assertStringNotContainsString('acme/lib/functions.php', $result['output']);
+  }
+
+  public function test_an_unreadable_folder_is_not_walked_noisily(): void
+  {
+    mkdir($this->bones->plugin . '/assets/private', 0777, true);
+    chmod($this->bones->plugin . '/assets/private', 0);
+
+    try {
+      $result = $this->deploy();
+    } finally {
+      chmod($this->bones->plugin . '/assets/private', 0755);
+    }
+
+    $this->assertSame(0, $result['status'], $result['output']);
+    $this->assertStringNotContainsString('Warning', $result['output']);
+  }
+
+  public function test_the_code_beside_the_tests_still_ships(): void
+  {
+    $result = $this->deploy('--wp');
+
+    $this->assertSame(0, $result['status'], $result['output']);
+    $this->assertFileExists($this->target . '/plugin/Http/Controllers/TestController.php');
+    $this->assertFileExists($this->target . '/resources/assets/apps/utils/format.ts');
+    $this->assertFileExists($this->target . '/resources/assets/apps/utils/latest.ts');
+  }
+
+  public function test_vendor_is_left_as_composer_installed_it(): void
+  {
+    $result = $this->deploy();
+
+    $this->assertSame(0, $result['status'], $result['output']);
+    $this->assertFileExists($this->target . '/vendor/acme/lib/__tests__/lib.test.js');
+  }
+}