diff --git a/.gitignore b/.gitignore
index eed7ff6..9b6cffc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,5 @@
 
 # PHPStorm
 **/.idea/
+
+**/.cache/
diff --git a/Dockerfile b/Dockerfile
new file mode 100644
index 0000000..3e14266
--- /dev/null
+++ b/Dockerfile
@@ -0,0 +1,22 @@
+FROM composer:lts as deps
+WORKDIR /app
+RUN --mount=type=bind,source=./composer.json,target=composer.json \
+    --mount=type=bind,source=./composer.lock,target=composer.lock \
+    --mount=type=cache,target=/tmp/cache \
+    composer install --no-interaction
+
+FROM php:8-cli as base
+WORKDIR /app
+RUN apt-get update &&  \
+    apt-get install -yq --no-install-recommends libsqlite3-dev &&  \
+    rm -rf /var/lib/apt/lists/* &&  \
+    docker-php-ext-install pdo pdo_sqlite
+COPY ./src /app/src
+
+FROM base as dev
+COPY ./tests /app/tests
+RUN mv "$PHP_INI_DIR/php.ini-development" "$PHP_INI_DIR/php.ini"
+COPY --from=deps /app/vendor/ /app/vendor
+
+FROM dev as test
+ENTRYPOINT [ "./vendor/bin/phpunit" ]
diff --git a/compose.yml b/compose.yml
new file mode 100644
index 0000000..97f3091
--- /dev/null
+++ b/compose.yml
@@ -0,0 +1,5 @@
+services:
+  database:
+    build: .
+    volumes:
+      - ./:/app
diff --git a/composer.json b/composer.json
index 85a3f71..e415bf2 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,7 @@
 {
     "name": "provm/database",
     "type": "library",
+    "version": "1.2.0",
     "authors": [
         {
             "name": "Aldarien",
@@ -12,8 +13,7 @@
         "ext-pdo": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^10.0",
-        "kint-php/kint": "^5.0"
+        "phpunit/phpunit": "^10.0"
     },
     "autoload": {
         "psr-4": {
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..fcc4184
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         cacheResultFile=".cache/test-results"
+         executionOrder="depends,defects"
+         forceCoversAnnotation="false"
+         beStrictAboutCoversAnnotation="true"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         convertDeprecationsToExceptions="true"
+         colors="true"
+         failOnRisky="true"
+         failOnWarning="true"
+         verbose="true">
+    <testsuites>
+        <testsuite name="default">
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+
+    <coverage cacheDirectory=".cache/code-coverage"
+              processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </coverage>
+</phpunit>
diff --git a/src/Database/Connection.php b/src/Database/Connection.php
index 934eba4..ab67de3 100644
--- a/src/Database/Connection.php
+++ b/src/Database/Connection.php
@@ -3,6 +3,7 @@ namespace ProVM\Database;
 
 use PDO;
 use ProVM\Concept\Database;
+use ProVM\Exception\Database\InvalidQuery;
 
 class Connection implements Database\Connection
 {
@@ -50,11 +51,19 @@ class Connection implements Database\Connection
 
     public function query(string $query): Database\ResultSet
     {
-        return new ResultSet($this->connect()->query($query));
+        $statement = $this->connect()->query($query);
+        if ($statement === false) {
+            throw new InvalidQuery($query);
+        }
+        return new ResultSet($statement);
     }
     public function prepare(string $query): Database\ResultSet
     {
-        return new ResultSet($this->connect()->prepare($query));
+        $statement = $this->connect()->prepare($query);
+        if ($statement === false) {
+            throw new InvalidQuery($query);
+        }
+        return new ResultSet($statement);
     }
     public function execute(string $query, ?array $data = null): Database\ResultSet
     {
@@ -65,4 +74,13 @@ class Connection implements Database\Connection
         }
         return $this->query($query);
     }
+
+    public function fetchOne(string $query, ?array $data = null): array
+    {
+        return $this->execute($query, $data)->fetchFirst();
+    }
+    public function fetchMany(string $query, ?array $data = null): array
+    {
+        return $this->execute($query, $data)->fetchAll();
+    }
 }
diff --git a/src/Exception/Database/InvalidQuery.php b/src/Exception/Database/InvalidQuery.php
new file mode 100644
index 0000000..4f9b48c
--- /dev/null
+++ b/src/Exception/Database/InvalidQuery.php
@@ -0,0 +1,14 @@
+<?php
+namespace ProVM\Exception\Database;
+
+use Throwable;
+use ProVM\Exception;
+
+class InvalidQuery extends Exception\Database
+{
+    public function __construct(string $query, ?Throwable $previous = null)
+    {
+        $message = "Invalid query \"{$query}\"";
+        parent::__construct($message, 0, $previous);
+    }
+}
diff --git a/tests/ConnectionTest.php b/tests/ConnectionTest.php
new file mode 100644
index 0000000..fe4919f
--- /dev/null
+++ b/tests/ConnectionTest.php
@@ -0,0 +1,65 @@
+<?php
+use PHPUnit\Framework\TestCase;
+
+use ProVM\Database\Connection;
+use ProVM\Concept;
+
+class ConnectionTest extends TestCase
+{
+    protected PDO $pdo;
+    protected function setUp(): void
+    {
+        $this->pdo = new PDO('sqlite::memory:');
+        $query = "CREATE TABLE IF NOT EXISTS test_table (id INTEGER PRIMARY KEY, test TEXT)";
+        $this->pdo->query($query);
+    }
+    protected function tearDown(): void
+    {
+        unset($this->pdo);
+    }
+
+    public function testConnection()
+    {
+        $host = "memory";
+
+        $database = $this->getMockBuilder(Concept\Database::class)->getMock();
+        $database->method('getHost')->willReturn($host);
+        $database->method('getDsn')->willReturn("sqlite::{$host}");
+        $database->method('needsUser')->willReturn(false);
+
+        $connection = new Connection($database);
+        $this->assertEquals($this->pdo, $connection->connect());
+    }
+    public function testQuery()
+    {
+        $host = "memory";
+
+        $database = $this->getMockBuilder(Concept\Database::class)->getMock();
+        $database->method('getHost')->willReturn($host);
+        $database->method('getDsn')->willReturn("sqlite::{$host}");
+        $database->method('needsUser')->willReturn(false);
+
+        $connection = new Connection($database);
+        $query = "CREATE TABLE IF NOT EXISTS test_table (id INTEGER PRIMARY KEY, test TEXT)";
+        $connection->query($query);
+        $query = "SELECT * FROM test_table";
+        $result = $connection->query($query);
+        $this->assertInstanceOf(Concept\Database\ResultSet::class, $result);
+    }
+    public function testPrepare()
+    {
+        $host = "memory";
+
+        $database = $this->getMockBuilder(Concept\Database::class)->getMock();
+        $database->method('getHost')->willReturn($host);
+        $database->method('getDsn')->willReturn("sqlite::{$host}");
+        $database->method('needsUser')->willReturn(false);
+
+        $connection = new Connection($database);
+        $query = "CREATE TABLE IF NOT EXISTS test_table (id INTEGER PRIMARY KEY, test TEXT)";
+        $connection->query($query);
+        $query = "SELECT * FROM test_table";
+        $result = $connection->prepare($query);
+        $this->assertInstanceOf(Concept\Database\ResultSet::class, $result);
+    }
+}
diff --git a/tests/MySQLTest.php b/tests/MySQLTest.php
new file mode 100644
index 0000000..c02ede0
--- /dev/null
+++ b/tests/MySQLTest.php
@@ -0,0 +1,32 @@
+<?php
+use PHPUnit\Framework\TestCase;
+use ProVM\Database\MySQL;
+
+class MySQLTest extends TestCase
+{
+    public function testDatabase()
+    {
+        $host = "testhost";
+        $port = 1234;
+        $name = "testdb";
+        $user = "testuser";
+        $pass = "testpass";
+
+        $dsn = "mysql:host={$host};port={$port};dbname={$name}";
+
+        $database = new MySQL();
+        $database->setHost($host);
+        $database->setPort($port);
+        $database->setName($name);
+        $database->setUser($user);
+        $database->setPassword($pass);
+
+        $this->assertEquals($host, $database->getHost());
+        $this->assertEquals($port, $database->getPort());
+        $this->assertEquals($name, $database->getName());
+        $this->assertEquals($user, $database->getUser());
+        $this->assertEquals($pass, $database->getPassword());
+        $this->assertTrue($database->needsUser());
+        $this->assertEquals($dsn, $database->getDsn());
+    }
+}
diff --git a/tests/PostgreSQLTest.php b/tests/PostgreSQLTest.php
new file mode 100644
index 0000000..993005c
--- /dev/null
+++ b/tests/PostgreSQLTest.php
@@ -0,0 +1,32 @@
+<?php
+use PHPUnit\Framework\TestCase;
+use ProVM\Database\PostgreSQL;
+
+class PostgreSQLTest extends TestCase
+{
+    public function testDatabase()
+    {
+        $host = "testhost";
+        $port = 1234;
+        $name = "testdb";
+        $user = "testuser";
+        $pass = "testpass";
+
+        $dsn = "pgsql:host={$host};port={$port};dbname={$name};user={$user};password={$pass}";
+
+        $database = new PostgreSQL();
+        $database->setHost($host);
+        $database->setPort($port);
+        $database->setName($name);
+        $database->setUser($user);
+        $database->setPassword($pass);
+
+        $this->assertEquals($host, $database->getHost());
+        $this->assertEquals($port, $database->getPort());
+        $this->assertEquals($name, $database->getName());
+        $this->assertEquals($user, $database->getUser());
+        $this->assertEquals($pass, $database->getPassword());
+        $this->assertFalse($database->needsUser());
+        $this->assertEquals($dsn, $database->getDsn());
+    }
+}
diff --git a/tests/ResultSetTest.php b/tests/ResultSetTest.php
new file mode 100644
index 0000000..b64b4bf
--- /dev/null
+++ b/tests/ResultSetTest.php
@@ -0,0 +1,26 @@
+<?php
+use PHPUnit\Framework\TestCase;
+
+use ProVM\Database\ResultSet;
+
+class ResultSetTest extends TestCase
+{
+    public function testResultSet()
+    {
+        $result1 = ['col1', 'col2', 'col3'];
+        $result2 = [['col1', 'col2'], ['col3', 'col4']];
+
+        $statement = $this->getMockBuilder(PDOStatement::class)->getMock();
+        $statement->method('execute')->willReturn(true);
+        $statement->method('fetch')->willReturn($result1);
+        $statement->method('fetchAll')->willReturn($result2);
+        $statement->method('rowCount')->willReturn(2);
+
+        $resultSet = new ResultSet($statement);
+
+        $resultSet->execute(['foo' => 'bar']);
+        $this->assertTrue(true);
+        $this->assertEquals($result1, $resultSet->fetchFirst());
+        $this->assertEquals($result2, $resultSet->fetchAll());
+    }
+}
diff --git a/tests/SQLiteTest.php b/tests/SQLiteTest.php
new file mode 100644
index 0000000..b1d5820
--- /dev/null
+++ b/tests/SQLiteTest.php
@@ -0,0 +1,20 @@
+<?php
+use PHPUnit\Framework\TestCase;
+use ProVM\Database\SQLite;
+
+class SQLiteTest extends TestCase
+{
+    public function testDatabase()
+    {
+        $host = ":memory:";
+
+        $dsn = "sqlite:{$host}";
+
+        $database = new SQLite();
+        $database->setHost($host);
+
+        $this->assertEquals($host, $database->getHost());
+        $this->assertFalse($database->needsUser());
+        $this->assertEquals($dsn, $database->getDsn());
+    }
+}
diff --git a/tests/TransactionTest.php b/tests/TransactionTest.php
new file mode 100644
index 0000000..ec2ff0c
--- /dev/null
+++ b/tests/TransactionTest.php
@@ -0,0 +1,19 @@
+<?php
+use PHPUnit\Framework\TestCase;
+use ProVM\Database\Transaction;
+
+class TransactionTest extends TestCase
+{
+    public function testTransaction()
+    {
+        $connection = $this->createMock(ProVM\Concept\Database\Connection::class);
+        $transaction = new Transaction($connection);
+        $transaction->begin();
+        $this->assertTrue(true);
+        $transaction->commit();
+        $this->assertTrue(true);
+        $transaction->begin();
+        $transaction->rollback();
+        $this->assertTrue(true);
+    }
+}