diff --git a/.gitignore b/.gitignore
index 247dd84..d4843b1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ build/
 .buildpath
 .project
 composer.lock
+coverage.xml
diff --git a/.travis.yml b/.travis.yml
index 17db0d6..60508d0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,12 +1,17 @@
 language: php
 
 php:
+  - 5.6
   - 7.1
   - 7.2
+  - 7.3
 
 before_script:
   - travis_retry composer self-update
   - travis_retry composer update --no-interaction
 
 script:
-  - vendor/bin/phpunit
\ No newline at end of file
+  - composer test-cover
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)
diff --git a/composer.json b/composer.json
index 58b2557..39f2efb 100644
--- a/composer.json
+++ b/composer.json
@@ -10,18 +10,26 @@
     }
   ],
   "require": {
-    "php": ">=5.4",
+    "php": "^5.6 | ^7.0",
     "doctrine/dbal": "~2.4",
     "doctrine/orm": "~2.4"
   },
   "require-dev": {
-    "phpunit/phpunit": "^6.5"
+    "phpunit/phpunit": "^5.7 | ^6.5"
   },
   "autoload": {
     "psr-4": {
       "Opsway\\": "src/"
     }
   },
+  "autoload-dev": {
+    "psr-4": {
+      "OpsWay\\Tests\\": "tests/"
+    }
+  },
+  "scripts": {
+    "test-cover": "phpunit --coverage-clover=coverage.xml"
+  },
   "extra": {
     "branch-alias": {
       "dev-master": "1.0-dev"
diff --git a/tests/EmTestCase.php b/tests/EmTestCase.php
new file mode 100644
index 0000000..10719ba
--- /dev/null
+++ b/tests/EmTestCase.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace OpsWay\Tests;
+
+use Doctrine\ORM\EntityManager;
+use Doctrine\ORM\Tools\Setup;
+use PHPUnit\Framework\TestCase;
+
+class EmTestCase extends TestCase
+{
+    /** @var EntityManager */
+    protected $em;
+
+    protected function customStringFunctions() : array
+    {
+        return [];
+    }
+
+    protected function setUp()
+    {
+        $config = Setup::createConfiguration(true);
+        $driverImpl = $config->newDefaultAnnotationDriver([__DIR__]);
+        $config->setMetadataDriverImpl($driverImpl);
+        $this->em = EntityManager::create([
+            'driver' => 'pdo_sqlite',
+            'memory' => true,
+        ], $config);
+
+        foreach ($this->customStringFunctions() as $name => $className) {
+            $this->em->getConfiguration()->addCustomStringFunction($name, $className);
+        }
+    }
+}
+
diff --git a/tests/Entity.php b/tests/Entity.php
new file mode 100644
index 0000000..a03d7ba
--- /dev/null
+++ b/tests/Entity.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace OpsWay\Tests;
+
+/** @Entity */
+class Entity
+{
+    /** @Id @Column(type="string") @GeneratedValue */
+    private $id;
+
+    /**
+     * @var array
+     * @Column(type="json", nullable=true, options={"jsonb": true})
+     */
+    private $metaData;
+}
diff --git a/tests/Unit/ORM/Query/AST/Functions/TsConcatTest.php b/tests/Unit/ORM/Query/AST/Functions/TsConcatTest.php
index 615e881..9436cdc 100644
--- a/tests/Unit/ORM/Query/AST/Functions/TsConcatTest.php
+++ b/tests/Unit/ORM/Query/AST/Functions/TsConcatTest.php
@@ -1,41 +1,38 @@
 <?php
 
-namespace Opsway\Tests\Doctrine\ORM\Query\AST\Functions;
+namespace OpsWay\Tests\Doctrine\ORM\Query\AST\Functions;
 
-use Doctrine\ORM\Query\AST\ParenthesisExpression;
-use Doctrine\ORM\Query\Lexer;
-use Doctrine\ORM\Query\Parser;
-use Doctrine\ORM\Query\SqlWalker;
+use OpsWay\Tests\EmTestCase;
 use Opsway\Doctrine\ORM\Query\AST\Functions\TsConcat;
-use PHPUnit\Framework\TestCase;
 
-class TsConcatTest extends TestCase
+class TsConcatTest extends EmTestCase
 {
-    private $tsConcat;
-
-    public function setUp()
+    protected function customStringFunctions() : array
     {
-        $this->tsConcat = new TsConcat('test');
+        return [
+            'TS_CONCAT_OP' => TsConcat::class,
+        ];
     }
 
-    public function testFunction()
+    /** @dataProvider functionData */
+    public function testFunction(string $dql, string $sql)
     {
-        $parser = $this->prophesize(Parser::class);
-        $expr = $this->prophesize(ParenthesisExpression::class);
-        $lexer = $this->prophesize(Lexer::class);
-
-        $parser->match()->shouldBeCalled()->withArguments([Lexer::T_IDENTIFIER]);
-        $parser->match()->shouldBeCalled()->withArguments([Lexer::T_OPEN_PARENTHESIS]);
-        $parser->StringPrimary()->shouldBeCalled()->willReturn($expr->reveal());
-        $parser->match()->shouldBeCalled()->withArguments([Lexer::T_COMMA]);
-        $parser->match()->shouldBeCalled()->withArguments([Lexer::T_CLOSE_PARENTHESIS]);
-        $parser->getLexer()->shouldBeCalled()->willReturn($lexer->reveal());
-        $sqlWalker = $this->prophesize(SqlWalker::class);
-
-        $this->tsConcat->parse($parser->reveal());
-
-        $expr->dispatch()->shouldBeCalled()->withArguments([$sqlWalker->reveal()])->willReturn('test');
+        $query = $this->em->createQuery($dql);
+        $this->assertEquals($sql, $query->getSql());
+    }
 
-        $this->assertEquals('test || test', $this->tsConcat->getSql($sqlWalker->reveal()));
+    public function functionData()
+    {
+        return [
+            [
+                'SELECT TS_CONCAT_OP(e.id, e.id) FROM OpsWay\Tests\Entity e',
+                'SELECT e0_.id || e0_.id AS sclr_0 FROM Entity e0_',
+            ],
+            [
+                'SELECT TS_CONCAT_OP(e.id, e.id, e.id) FROM OpsWay\Tests\Entity e',
+                'SELECT e0_.id || e0_.id || e0_.id AS sclr_0 FROM Entity e0_',
+            ],
+        ];
     }
 }
+