diff --git a/tests/Support/Assert.php b/tests/Support/Assert.php
deleted file mode 100644
index 92d398f..0000000
--- a/tests/Support/Assert.php
+++ /dev/null
@@ -1,100 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Yiisoft\Db\Tests\Support;
-
-use PHPUnit\Framework\TestCase;
-use ReflectionClass;
-use ReflectionException;
-use ReflectionObject;
-
-/**
- * @psalm-suppress PropertyNotSetInConstructor
- */
-final class Assert extends TestCase
-{
-    /**
-     * Asserts that value is one of expected values.
-     */
-    public static function isOneOf(mixed $actual, array $expected, string $message = ''): void
-    {
-        self::assertThat($actual, new IsOneOfAssert($expected), $message);
-    }
-
-    /**
-     * Asserting two strings equality ignoring line endings.
-     */
-    public static function equalsWithoutLE(string $expected, string $actual, string $message = ''): void
-    {
-        $expected = str_replace("\r\n", "\n", $expected);
-        $actual = str_replace("\r\n", "\n", $actual);
-
-        self::assertEquals($expected, $actual, $message);
-    }
-
-    /**
-     * Gets an inaccessible object property.
-     *
-     * @param bool $revoke whether to make property inaccessible after getting.
-     */
-    public static function getInaccessibleProperty(object $object, string $propertyName, bool $revoke = true): mixed
-    {
-        $class = new ReflectionClass($object);
-
-        while (!$class->hasProperty($propertyName)) {
-            $class = $class->getParentClass();
-        }
-
-        $property = $class->getProperty($propertyName);
-
-        $property->setAccessible(true);
-
-        /** @psalm-var mixed $result */
-        $result = $property->getValue($object);
-
-        if ($revoke) {
-            $property->setAccessible(false);
-        }
-
-        return $result;
-    }
-
-    /**
-     * Sets an inaccessible object property.
-     *
-     * @param object $object The object to set the property on.
-     * @param string $propertyName The name of the property to set.
-     * @param mixed $value The value to set.
-     */
-    public static function setInaccessibleProperty(object $object, string $propertyName, mixed $value): void
-    {
-        $class = new ReflectionClass($object);
-
-        while (!$class->hasProperty($propertyName)) {
-            $class = $class->getParentClass();
-        }
-
-        $property = $class->getProperty($propertyName);
-        $property->setAccessible(true);
-        $property->setValue($object, $value);
-    }
-
-    /**
-     * Invokes an inaccessible method.
-     *
-     * @param object $object The object to invoke the method on.
-     * @param string $method The name of the method to invoke.
-     * @param array $args The arguments to pass to the method.
-     *
-     * @throws ReflectionException
-     */
-    public static function invokeMethod(object $object, string $method, array $args = []): mixed
-    {
-        $reflection = new ReflectionObject($object);
-        $method = $reflection->getMethod($method);
-        $method->setAccessible(true);
-
-        return $method->invokeArgs($object, $args);
-    }
-}
diff --git a/tests/Support/DbHelper.php b/tests/Support/DbHelper.php
deleted file mode 100644
index 04112cf..0000000
--- a/tests/Support/DbHelper.php
+++ /dev/null
@@ -1,67 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Yiisoft\Data\Db\Tests\Support;
-
-use Yiisoft\Db\Driver\Pdo\PdoConnectionInterface;
-use Yiisoft\Db\Exception\Exception;
-use Yiisoft\Db\Exception\InvalidConfigException;
-
-use function explode;
-use function file_get_contents;
-use function preg_replace;
-use function str_replace;
-use function trim;
-
-final class DbHelper
-{
-    /**
-     * Loads the fixture into the database.
-     *
-     * @throws Exception
-     * @throws InvalidConfigException
-     */
-    public static function loadFixture(PdoConnectionInterface $db, string $fixture): void
-    {
-        $db->open();
-
-        if ($db->getDriverName() === 'oci') {
-            [$drops, $creates] = explode('/* STATEMENTS */', file_get_contents($fixture), 2);
-            [$statements, $triggers, $data] = explode('/* TRIGGERS */', $creates, 3);
-            $lines = array_merge(
-                explode('--', $drops),
-                explode(';', $statements),
-                explode('/', $triggers),
-                explode(';', $data)
-            );
-        } else {
-            $lines = explode(';', file_get_contents($fixture));
-        }
-
-        foreach ($lines as $line) {
-            if (trim($line) !== '') {
-                $db->getPDO()?->exec($line);
-            }
-        }
-    }
-
-    /**
-     * Adjust dbms specific escaping.
-     *
-     * @param string $sql string SQL statement to adjust.
-     * @param string $driverName string DBMS name.
-     *
-     * @return mixed
-     */
-    public static function replaceQuotes(string $sql, string $driverName): string
-    {
-        return match ($driverName) {
-            'mysql', 'sqlite' => str_replace(['[[', ']]'], '`', $sql),
-            'oci' => str_replace(['[[', ']]'], '"', $sql),
-            'pgsql' => str_replace(['\\[', '\\]'], ['[', ']'], preg_replace('/(\[\[)|((?<!(\[))]])/', '"', $sql)),
-            'db', 'sqlsrv' => str_replace(['[[', ']]'], ['[', ']'], $sql),
-            default => $sql,
-        };
-    }
-}
diff --git a/tests/Support/TraversableObject.php b/tests/Support/TraversableObject.php
deleted file mode 100644
index eadfad6..0000000
--- a/tests/Support/TraversableObject.php
+++ /dev/null
@@ -1,57 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Yiisoft\Db\Tests\Support;
-
-use Countable;
-use Exception;
-use Iterator;
-
-/**
- * TraversableObject
- *
- * Object that implements `Traversable` and `Countable`, but counting throws an exception;
- * Used for testing support for traversable objects instead of arrays.
- */
-final class TraversableObject implements Iterator, Countable
-{
-    private int $position = 0;
-
-    public function __construct(protected array $data)
-    {
-    }
-
-    /**
-     * @throws Exception
-     */
-    public function count(): int
-    {
-        throw new Exception('Count called on object that should only be traversed.');
-    }
-
-    public function current(): mixed
-    {
-        return $this->data[$this->position];
-    }
-
-    public function next(): void
-    {
-        $this->position++;
-    }
-
-    public function key(): int
-    {
-        return $this->position;
-    }
-
-    public function valid(): bool
-    {
-        return array_key_exists($this->position, $this->data);
-    }
-
-    public function rewind(): void
-    {
-        $this->position = 0;
-    }
-}