diff --git a/.travis.yml b/.travis.yml
index 1b81b89..76aa707 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,7 +36,11 @@ before_install:
   - sudo service elasticsearch restart
 before_script:
   - |
-    [[ $COVERAGE == "true" ]] || phpenv config-rm xdebug.ini
+    if [[ $COVERAGE == "true" ]]; then \
+      pecl install -f xdebug-2.9.8 #see https://github.com/magento/magento2/issues/28961 \
+    else
+      phpenv config-rm xdebug.ini
+    fi
     ./.travis/before_script.sh
 script: phpunit -c magento2/dev/tests/$TEST_SUITE `[[ $COVERAGE == "true" ]] && echo "--coverage-text --coverage-clover=/tmp/coverage.clover"`
 after_script:
diff --git a/.travis/before_script.sh b/.travis/before_script.sh
index 85c2aaf..dc8acbb 100755
--- a/.travis/before_script.sh
+++ b/.travis/before_script.sh
@@ -13,7 +13,7 @@ echo 'sendmail_path = "/usr/sbin/sendmail -t -i "' > ~/.phpenv/versions/$(phpenv
 echo 'memory_limit = -1' >> ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/travis.ini
 phpenv rehash;
 
-composer selfupdate
+composer selfupdate --1
 
 # clone main magento github repository
 git clone --branch $MAGENTO_VERSION --depth=1 https://github.com/magento/magento2
@@ -49,8 +49,11 @@ case $TEST_SUITE in
             SET @@global.sql_mode = NO_ENGINE_SUBSTITUTION;
             CREATE DATABASE magento_integration_tests;
         '
-        cp etc/install-config-mysql.travis.php.dist etc/install-config-mysql.php
+        cp etc/install-config-mysql.php.dist etc/install-config-mysql.php
+        # Remove AMQP configuration
         sed -i '/amqp/d' etc/install-config-mysql.php
+        # Remove default root password
+        sed -i 's/123123q//' etc/install-config-mysql.php
 
         cd ../../..
         echo "Wait for ElasticSearch on port 9200..."
diff --git a/src/Theme/ThemeFixture.php b/src/Theme/ThemeFixture.php
new file mode 100644
index 0000000..efc1f78
--- /dev/null
+++ b/src/Theme/ThemeFixture.php
@@ -0,0 +1,37 @@
+<?php
+declare(strict_types=1);
+
+namespace TddWizard\Fixtures\Theme;
+
+use Magento\Framework\View\DesignInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+use Magento\Theme\Model\Theme\Registration;
+
+/**
+ * A fixture to test theme features, e.g. with with test themes in `@magentoComponentsDir`
+ */
+class ThemeFixture
+{
+
+    /**
+     * Register new themes from the `@magentoComponentsDir` fixture in the database
+     */
+    public static function registerTestThemes(): void
+    {
+        /** @var Registration $registration */
+        $registration = Bootstrap::getObjectManager()->get(Registration::class);
+        $registration->register();
+    }
+
+    /**
+     * Set the current theme
+     *
+     * @param string $themePath a theme identifier without the area, e.g. Magento/luma
+     */
+    public static function setCurrentTheme(string $themePath): void
+    {
+        /** @var DesignInterface $design */
+        $design = Bootstrap::getObjectManager()->get(DesignInterface::class);
+        $design->setDesignTheme($themePath);
+    }
+}
diff --git a/tests/Catalog/IndexerErrorsTest.php b/tests/Catalog/IndexerErrorsTest.php
index 30b073a..7c21727 100644
--- a/tests/Catalog/IndexerErrorsTest.php
+++ b/tests/Catalog/IndexerErrorsTest.php
@@ -19,11 +19,13 @@ class IndexerErrorsTest extends TestCase
     private static $indexIsScheduledOrig;
 
     /**
+     * @deprecated the test should be removed in next release, but we should still keep the exception in case this
+     *             happens again
      * @magentoDataFixture Magento/Store/_files/second_website_with_two_stores.php
      */
     public function testHelpfulErrorMessageForFulltextIndexSchedule()
     {
-        $this->onlyRunFromMagento('2.3.0');
+        $this->markTestSkipped('Since Magento 2.3.6 / 2.4.1 these transaction exceptions do not occur anymore');
         $this->expectException(\Exception::class);
 
         try {
@@ -58,13 +60,4 @@ public static function disableReindexScheduleRollback()
         $model = Bootstrap::getObjectManager()->get(IndexerRegistry::class)->get('catalogsearch_fulltext');
         $model->setScheduled(self::$indexIsScheduledOrig);
     }
-
-    private function onlyRunFromMagento($magentoVersion): void
-    {
-        /** @var ProductMetadataInterface $productMetadata */
-        $productMetadata = Bootstrap::getObjectManager()->get(ProductMetadataInterface::class);
-        if (version_compare($productMetadata->getVersion(), $magentoVersion, '<')) {
-            $this->markTestSkipped('Only relevant for Magento >= ' . $magentoVersion . '');
-        }
-    }
 }
diff --git a/tests/Theme/ThemeFixtureTest.php b/tests/Theme/ThemeFixtureTest.php
new file mode 100644
index 0000000..58b6921
--- /dev/null
+++ b/tests/Theme/ThemeFixtureTest.php
@@ -0,0 +1,35 @@
+<?php
+declare(strict_types=1);
+
+namespace TddWizard\Fixtures\Theme;
+
+use Magento\Framework\View\DesignInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @magentoAppIsolation enabled
+ * @magentoAppArea frontend
+ * @magentoComponentsDir ../../../../vendor/tddwizard/magento2-fixtures/tests/Theme/_files/design
+ */
+class ThemeFixtureTest extends TestCase
+{
+    public function testSetCurrentFrontendTheme()
+    {
+        ThemeFixture::setCurrentTheme('Magento/blank');
+        /** @var DesignInterface $design */
+        $design = Bootstrap::getObjectManager()->get(DesignInterface::class);
+        $this->assertEquals('Magento/blank', $design->getDesignTheme()->getCode());
+    }
+
+    public function testCanUseTestThemeAfterRegistering()
+    {
+        ThemeFixture::registerTestThemes();
+        ThemeFixture::setCurrentTheme('Custom/default');
+        /** @var DesignInterface $design */
+        $design = Bootstrap::getObjectManager()->get(DesignInterface::class);
+        $this->assertEquals('Custom/default', $design->getDesignTheme()->getCode());
+        $this->assertGreaterThan(0, $design->getDesignTheme()->getId());
+        $this->assertEquals('Magento/blank', $design->getDesignTheme()->getParentTheme()->getCode());
+    }
+}
diff --git a/tests/Theme/_files/design/frontend/Custom/default/registration.php b/tests/Theme/_files/design/frontend/Custom/default/registration.php
new file mode 100644
index 0000000..6e8486d
--- /dev/null
+++ b/tests/Theme/_files/design/frontend/Custom/default/registration.php
@@ -0,0 +1,11 @@
+<?php
+/**
+ * Hyvä Themes - https://hyva.io
+ * Copyright © Hyvä Themes 2020-present. All rights reserved.
+ * This product is licensed per Magento install
+ * See https://hyva.io/license
+ */
+
+use \Magento\Framework\Component\ComponentRegistrar;
+
+ComponentRegistrar::register(ComponentRegistrar::THEME, 'frontend/Custom/default', __DIR__);
diff --git a/tests/Theme/_files/design/frontend/Custom/default/theme.xml b/tests/Theme/_files/design/frontend/Custom/default/theme.xml
new file mode 100644
index 0000000..03fbf54
--- /dev/null
+++ b/tests/Theme/_files/design/frontend/Custom/default/theme.xml
@@ -0,0 +1,12 @@
+<!--
+/**
+ * Hyvä Themes - https://hyva.io
+ * Copyright © Hyvä Themes 2020-present. All rights reserved.
+ * This product is licensed per Magento install
+ * See https://hyva.io/license
+ */
+-->
+<theme xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Config/etc/theme.xsd">
+    <title>Test theme</title>
+    <parent>Magento/blank</parent>
+</theme>