From b7685a180cf28210031ec7bc99bb99e4f11d7d59 Mon Sep 17 00:00:00 2001
From: Charles Sprayberry <me@cspray.io>
Date: Thu, 2 Mar 2023 10:27:10 -0500
Subject: [PATCH 1/3] Add declare strict types

---
 src/ConnectionAdapter.php                     | 2 +-
 src/ConnectionAdapterConfig.php               | 2 +-
 src/DatabaseRepresentation/Row.php            | 2 +-
 src/DatabaseTestCase.php                      | 5 +----
 src/Exception/ConnectionNotYetEstablished.php | 2 +-
 src/Exception/InvalidFixture.php              | 2 +-
 src/Exception/MissingRequiredExtension.php    | 2 +-
 src/Exception/UnableToGetTable.php            | 2 +-
 src/Fixture.php                               | 2 +-
 src/FixtureRecord.php                         | 2 +-
 src/LoadFixture.php                           | 2 +-
 src/PdoConnectionAdapter.php                  | 2 +-
 src/PdoDriver.php                             | 2 +-
 src/SingleRecordFixture.php                   | 2 +-
 14 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/src/ConnectionAdapter.php b/src/ConnectionAdapter.php
index 078773f..407e12b 100644
--- a/src/ConnectionAdapter.php
+++ b/src/ConnectionAdapter.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/ConnectionAdapterConfig.php b/src/ConnectionAdapterConfig.php
index fd0c8ab..e137e16 100644
--- a/src/ConnectionAdapterConfig.php
+++ b/src/ConnectionAdapterConfig.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/DatabaseRepresentation/Row.php b/src/DatabaseRepresentation/Row.php
index 6a4edc4..5a506a6 100644
--- a/src/DatabaseRepresentation/Row.php
+++ b/src/DatabaseRepresentation/Row.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase\DatabaseRepresentation;
 
diff --git a/src/DatabaseTestCase.php b/src/DatabaseTestCase.php
index 8ceb7f9..ffb4b7b 100644
--- a/src/DatabaseTestCase.php
+++ b/src/DatabaseTestCase.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
@@ -7,9 +7,6 @@
 use PHPUnit\Framework\TestCase;
 use ReflectionMethod;
 
-/**
- *
- */
 abstract class DatabaseTestCase extends TestCase {
 
     private static ?ConnectionAdapter $connectionAdapter;
diff --git a/src/Exception/ConnectionNotYetEstablished.php b/src/Exception/ConnectionNotYetEstablished.php
index 389ba68..8416df9 100644
--- a/src/Exception/ConnectionNotYetEstablished.php
+++ b/src/Exception/ConnectionNotYetEstablished.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase\Exception;
 
diff --git a/src/Exception/InvalidFixture.php b/src/Exception/InvalidFixture.php
index 14aa638..2ea7428 100644
--- a/src/Exception/InvalidFixture.php
+++ b/src/Exception/InvalidFixture.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase\Exception;
 
diff --git a/src/Exception/MissingRequiredExtension.php b/src/Exception/MissingRequiredExtension.php
index 873f807..40ee1a9 100644
--- a/src/Exception/MissingRequiredExtension.php
+++ b/src/Exception/MissingRequiredExtension.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase\Exception;
 
diff --git a/src/Exception/UnableToGetTable.php b/src/Exception/UnableToGetTable.php
index 6cfd4e7..5d8402b 100644
--- a/src/Exception/UnableToGetTable.php
+++ b/src/Exception/UnableToGetTable.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase\Exception;
 
diff --git a/src/Fixture.php b/src/Fixture.php
index 68f4e45..9d5d8b7 100644
--- a/src/Fixture.php
+++ b/src/Fixture.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/FixtureRecord.php b/src/FixtureRecord.php
index 355933f..3e4a644 100644
--- a/src/FixtureRecord.php
+++ b/src/FixtureRecord.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/LoadFixture.php b/src/LoadFixture.php
index 4bb2a3d..2957987 100644
--- a/src/LoadFixture.php
+++ b/src/LoadFixture.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/PdoConnectionAdapter.php b/src/PdoConnectionAdapter.php
index 2ea8dc5..7405142 100644
--- a/src/PdoConnectionAdapter.php
+++ b/src/PdoConnectionAdapter.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/PdoDriver.php b/src/PdoDriver.php
index 8272c6e..edab1e7 100644
--- a/src/PdoDriver.php
+++ b/src/PdoDriver.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 
diff --git a/src/SingleRecordFixture.php b/src/SingleRecordFixture.php
index 0a2a033..6f6a09d 100644
--- a/src/SingleRecordFixture.php
+++ b/src/SingleRecordFixture.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Cspray\DatabaseTestCase;
 

From aab6d42d1bff1b293130e36e2b5a81ff1649ea19 Mon Sep 17 00:00:00 2001
From: Charles Sprayberry <me@cspray.io>
Date: Thu, 2 Mar 2023 16:43:56 -0500
Subject: [PATCH 2/3] Add support for amphp/postgres

---
 .gitignore                                    |  3 +-
 CHANGELOG.md                                  | 28 ++++++++
 composer.json                                 |  6 +-
 docker/php/Dockerfile                         |  2 +-
 src/AbstractConnectionAdapter.php             | 67 +++++++++++++++++++
 src/AmpPostgresConnectionAdapter.php          | 65 ++++++++++++++++++
 .../MissingRequiredComposerPackage.php        |  9 +++
 src/PdoConnectionAdapter.php                  | 57 +++-------------
 .../AmpPostgresConnectionAdapterTest.php      | 29 ++++++++
 .../Helper/PostgresConnectionConfig.php       | 19 ++++++
 .../PostgresPdoConnectionAdapterTest.php      | 13 ++--
 11 files changed, 240 insertions(+), 58 deletions(-)
 create mode 100644 CHANGELOG.md
 create mode 100644 src/AbstractConnectionAdapter.php
 create mode 100644 src/AmpPostgresConnectionAdapter.php
 create mode 100644 src/Exception/MissingRequiredComposerPackage.php
 create mode 100644 tests/Integration/AmpPostgresConnectionAdapterTest.php
 create mode 100644 tests/Integration/Helper/PostgresConnectionConfig.php

diff --git a/.gitignore b/.gitignore
index 1649674..046fe40 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,4 +2,5 @@
 ..
 /vendor
 .phpunit.cache
-.phpunit.result.cache
\ No newline at end of file
+.phpunit.result.cache
+composer.lock
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..19a32ae
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,28 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## Unreleased Changes
+
+### Added
+
+- Introduces a `Cspray\DatabaseTestCase\AbstractConnectionAdapter` for implementing functionality common across all `Cspray\DatabaseTestCase\ConnectionAdapter` implementations.
+- Provides the `Cspray\DatabaseTestCase\AmpPostgresConnectionAdapter` for working with the amphp/postgres library.
+
+### Changed
+
+- The `Cspray\DatabaseTestCase\PdoConnectionAdapter` now extends the new `AbstractConnectionAdapter` and has been simplified.
+- Added `declare(strict_types=1)` in all files it was missing.
+
+## [0.1.0](https://github.com/cspray/database-test-case/releases/tag/0.1.0) - 2023-03-02
+
+### Added
+
+- Adds a `Cspray\DatabaseTestCase\DatabaseTestCase` that allows for testing database interactions.
+- Adds a `Cspray\DatabaseTestCase\ConnectionAdapter` interface that is responsible for actual calls to an underlying connection.
+- Provides a `Cspray\DatabaseTestCase\PdoConnectionAdapter` with support for PostgreSQL databases.
+- Provides a mechanism for loading fixtures per test, using the Attribute `#[LoadFixture]` and providing an implementation of `Cspray\DatabaseTestCase\Fixture`.
+- Provides a mechanism for retrieving the state of a database table at a given point in time with `Cspray\DatabaseTestCase\DatabaseRepresentation\Table`.
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 17847d4..cb42dcb 100644
--- a/composer.json
+++ b/composer.json
@@ -7,6 +7,8 @@
     "database"
   ],
   "license": ["MIT"],
+  "minimum-stability": "beta",
+  "prefer-stable": true,
   "require": {
     "php": "^8.2",
     "phpunit/phpunit": "^10.0"
@@ -14,6 +16,7 @@
   "require-dev": {
     "ext-pdo": "*",
     "ext-pdo_pgsql": "*",
+    "amphp/postgres": "^v2.0.0-beta.2",
     "roave/security-advisories": "dev-latest"
   },
   "autoload": {
@@ -27,6 +30,7 @@
     }
   },
   "suggest": {
-    "ext-pdo": "To enable the PdoConnectionAdapter"
+    "ext-pdo": "To enable the PdoConnectionAdapter",
+    "amphp/postgres": "To enable the AmpPostgresConnectionAdapter"
   }
 }
\ No newline at end of file
diff --git a/docker/php/Dockerfile b/docker/php/Dockerfile
index 6e41a56..4c719e0 100644
--- a/docker/php/Dockerfile
+++ b/docker/php/Dockerfile
@@ -4,7 +4,7 @@ RUN apt-get update -y \
     && apt-get upgrade -y
 
 RUN apt-get install git libsodium-dev libzip-dev libpq-dev -y
-RUN docker-php-ext-install sodium zip pdo pdo_pgsql
+RUN docker-php-ext-install sodium zip pdo pdo_pgsql pgsql
 
 RUN mv "$PHP_INI_DIR/php.ini-development" "$PHP_INI_DIR/php.ini"
 
diff --git a/src/AbstractConnectionAdapter.php b/src/AbstractConnectionAdapter.php
new file mode 100644
index 0000000..1d6247a
--- /dev/null
+++ b/src/AbstractConnectionAdapter.php
@@ -0,0 +1,67 @@
+<?php declare(strict_types=1);
+
+namespace Cspray\DatabaseTestCase;
+
+use Cspray\DatabaseTestCase\DatabaseRepresentation\Row;
+use Cspray\DatabaseTestCase\DatabaseRepresentation\Table;
+use Cspray\DatabaseTestCase\Exception\UnableToGetTable;
+use Throwable;
+
+abstract class AbstractConnectionAdapter implements ConnectionAdapter {
+
+    final public function loadFixture(Fixture $fixture, Fixture ...$additionalFixture) : void {
+        /** @var Fixture $f */
+        foreach ([$fixture, ...$additionalFixture] as $f) {
+            foreach ($f->getFixtureRecords() as $fixtureRecord) {
+                $sql = $this->generateInsertSqlForParameters($fixtureRecord);
+                $parameters = $fixtureRecord->parameters;
+                $this->executeInsertSql($sql, $parameters);
+            }
+        }
+    }
+
+    final public function getTable(string $name) : Table {
+        try {
+            $table = Table::forName($name);
+            foreach ($this->executeSelectAllSql($name) as $row) {
+                $r = null;
+                foreach ($row as $col => $val) {
+                    $r = $r === null ? Row::forValue($col, $val) : $r->withValue($col, $val);
+                }
+                $table = $table->withRow($r);
+            }
+            return $table;
+        } catch (Throwable $throwable) {
+            throw new UnableToGetTable(
+                message: sprintf('Unable to fetch table "%s", please check previous Exception for more details.', $name),
+                previous: $throwable
+            );
+        }
+    }
+
+    protected function generateInsertSqlForParameters(FixtureRecord $fixtureRecord) : string {
+        $table = $fixtureRecord->table;
+        $parameters = $fixtureRecord->parameters;
+        $colsString = implode(
+            ', ',
+            array_keys($parameters)
+        );
+        $paramString = implode(
+            ', ',
+            array_map(static fn(string $col) => ':' . $col, array_keys($parameters))
+        );
+        return <<<SQL
+INSERT INTO $table ($colsString)
+VALUES ($paramString)
+SQL;
+    }
+
+    abstract protected function executeInsertSql(string $sql, array $parameters) : void;
+
+    /**
+     * @return list<array<string, mixed>>
+     * @throws Throwable
+     */
+    abstract protected function executeSelectAllSql(string $table) : array;
+
+}
diff --git a/src/AmpPostgresConnectionAdapter.php b/src/AmpPostgresConnectionAdapter.php
new file mode 100644
index 0000000..cf4d18b
--- /dev/null
+++ b/src/AmpPostgresConnectionAdapter.php
@@ -0,0 +1,65 @@
+<?php declare(strict_types=1);
+
+namespace Cspray\DatabaseTestCase;
+
+use Amp\Postgres\PostgresConfig;
+use Amp\Postgres\PostgresLink;
+use Cspray\DatabaseTestCase\Exception\MissingRequiredComposerPackage;
+use function Amp\Postgres\connect;
+
+if (! class_exists(PostgresLink::class)) {
+    throw new MissingRequiredComposerPackage('You must install amphp/postgres to use ' . AmpPostgresConnectionAdapter::class);
+}
+
+class AmpPostgresConnectionAdapter extends AbstractConnectionAdapter {
+
+    private ?PostgresLink $connection = null;
+
+    public function __construct(
+        private readonly ConnectionAdapterConfig $adapterConfig
+    ) {}
+
+    public function establishConnection() : void {
+        $this->connection = connect(
+            PostgresConfig::fromString(sprintf(
+                'db=%s host=%s port=%d user=%s pass=%s',
+                $this->adapterConfig->database,
+                $this->adapterConfig->host,
+                $this->adapterConfig->port,
+                $this->adapterConfig->user,
+                $this->adapterConfig->password
+            ))
+        );
+    }
+
+    public function onTestStart() : void {
+        $this->connection->query('START TRANSACTION');
+    }
+
+    public function onTestStop() : void {
+        $this->connection->query('ROLLBACK');
+    }
+
+    public function closeConnection() : void {
+        $this->connection->close();
+        $this->connection = null;
+    }
+
+    public function getUnderlyingConnection() : PostgresLink {
+        return $this->connection;
+    }
+
+    protected function executeInsertSql(string $sql, array $parameters) : void {
+        $statement = $this->connection->prepare($sql);
+        $statement->execute($parameters);
+    }
+
+    protected function executeSelectAllSql(string $table) : array {
+        $result = $this->connection->query(sprintf('SELECT * FROM %s', $table));
+        $rows = [];
+        while ($row = $result->fetchRow()) {
+            $rows[] = $row;
+        }
+        return $rows;
+    }
+}
diff --git a/src/Exception/MissingRequiredComposerPackage.php b/src/Exception/MissingRequiredComposerPackage.php
new file mode 100644
index 0000000..91ddf6b
--- /dev/null
+++ b/src/Exception/MissingRequiredComposerPackage.php
@@ -0,0 +1,9 @@
+<?php declare(strict_types=1);
+
+namespace Cspray\DatabaseTestCase\Exception;
+
+use RuntimeException;
+
+final class MissingRequiredComposerPackage extends RuntimeException {
+
+}
\ No newline at end of file
diff --git a/src/PdoConnectionAdapter.php b/src/PdoConnectionAdapter.php
index 7405142..0fe4e03 100644
--- a/src/PdoConnectionAdapter.php
+++ b/src/PdoConnectionAdapter.php
@@ -13,7 +13,7 @@
     throw new MissingRequiredExtension('You must enable ext-pdo to use the ' . PdoConnectionAdapter::class);
 }
 
-final class PdoConnectionAdapter implements ConnectionAdapter {
+final class PdoConnectionAdapter extends AbstractConnectionAdapter {
 
     private ?PDO $connection = null;
 
@@ -49,59 +49,22 @@ public function closeConnection() : void {
         $this->connection = null;
     }
 
-    public function loadFixture(Fixture $fixture, Fixture ...$additionalFixture) : void {
-        /** @var Fixture $f */
-        foreach ([$fixture, ...$additionalFixture] as $f) {
-            foreach ($f->getFixtureRecords() as $fixtureRecord) {
-                $statement = $this->connection->prepare($this->generateInsertSqlForParameters($fixtureRecord));
-                foreach ($fixtureRecord->parameters as $col => $val) {
-                    $statement->bindValue($col, $val);
-                }
-                $statement->execute();
-            }
-        }
-    }
 
     public function getUnderlyingConnection() : PDO {
         return $this->connection;
     }
 
-    public function getTable(string $name) : Table {
-        try {
-            $query = sprintf('SELECT * FROM %s', $name);
-            $result = $this->connection->query($query)->fetchAll(PDO::FETCH_ASSOC);
-            $table = Table::forName($name);
-            foreach ($result as $row) {
-                $r = null;
-                foreach ($row as $col => $val) {
-                    $r = $r === null ? Row::forValue($col, $val) : $r->withValue($col, $val);
-                }
-                $table = $table->withRow($r);
-            }
-            return $table;
-        } catch (PDOException $pdoException) {
-            throw new UnableToGetTable(
-                message: sprintf('Unable to fetch table "%s", please check previous Exception for more details.', $name),
-                previous: $pdoException
-            );
+
+    protected function executeInsertSql(string $sql, array $parameters) : void {
+        $statement = $this->getUnderlyingConnection()->prepare($sql);
+        foreach ($parameters as $col => $val) {
+            $statement->bindValue($col, $val);
         }
+        $statement->execute();
     }
 
-    private function generateInsertSqlForParameters(FixtureRecord $fixtureRecord) : string {
-        $table = $fixtureRecord->table;
-        $parameters = $fixtureRecord->parameters;
-        $colsString = implode(
-            ', ',
-            array_keys($parameters)
-        );
-        $paramString = implode(
-            ', ',
-            array_map(static fn(string $col) => ':' . $col, array_keys($parameters))
-        );
-        return <<<SQL
-INSERT INTO $table ($colsString)
-VALUES ($paramString)
-SQL;
+    protected function executeSelectAllSql(string $table) : array {
+        $query = sprintf('SELECT * FROM %s', $table);
+        return $this->connection->query($query)->fetchAll(PDO::FETCH_ASSOC);
     }
-
 }
diff --git a/tests/Integration/AmpPostgresConnectionAdapterTest.php b/tests/Integration/AmpPostgresConnectionAdapterTest.php
new file mode 100644
index 0000000..203bd21
--- /dev/null
+++ b/tests/Integration/AmpPostgresConnectionAdapterTest.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Cspray\DatabaseTestCase\Tests\Integration;
+
+use Amp\Postgres\PostgresLink;
+use Cspray\DatabaseTestCase\AmpPostgresConnectionAdapter;
+use Cspray\DatabaseTestCase\ConnectionAdapter;
+use Cspray\DatabaseTestCase\Tests\Integration\Helper\PostgresConnectionConfig;
+use PHPUnit\Framework\Attributes\CoversClass;
+
+#[CoversClass(AmpPostgresConnectionAdapter::class)]
+class AmpPostgresConnectionAdapterTest extends ConnectionAdapterTestCase {
+
+    protected function getExpectedUnderlyingConnectionClassName() : string {
+        return PostgresLink::class;
+    }
+
+    protected function executeCountSql(string $table) : int {
+        $connection = self::getUnderlyingConnection();
+        assert($connection instanceof PostgresLink);
+        return $connection->query('SELECT COUNT(*) AS count FROM ' . $table)->fetchRow()['count'];
+    }
+
+    protected static function getConnectionAdapter() : ConnectionAdapter {
+        return new AmpPostgresConnectionAdapter(
+            new PostgresConnectionConfig()
+        );
+    }
+}
\ No newline at end of file
diff --git a/tests/Integration/Helper/PostgresConnectionConfig.php b/tests/Integration/Helper/PostgresConnectionConfig.php
new file mode 100644
index 0000000..333ec6d
--- /dev/null
+++ b/tests/Integration/Helper/PostgresConnectionConfig.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace Cspray\DatabaseTestCase\Tests\Integration\Helper;
+
+use Cspray\DatabaseTestCase\ConnectionAdapterConfig;
+
+final class PostgresConnectionConfig extends ConnectionAdapterConfig {
+
+    public function __construct() {
+        parent::__construct(
+            'postgres',
+            'postgres',
+            5432,
+            'postgres',
+            'postgres'
+        );
+    }
+
+}
\ No newline at end of file
diff --git a/tests/Integration/PostgresPdoConnectionAdapterTest.php b/tests/Integration/PostgresPdoConnectionAdapterTest.php
index 1e35d81..9bf87e2 100644
--- a/tests/Integration/PostgresPdoConnectionAdapterTest.php
+++ b/tests/Integration/PostgresPdoConnectionAdapterTest.php
@@ -6,6 +6,7 @@
 use Cspray\DatabaseTestCase\ConnectionAdapterConfig;
 use Cspray\DatabaseTestCase\PdoConnectionAdapter;
 use Cspray\DatabaseTestCase\PdoDriver;
+use Cspray\DatabaseTestCase\Tests\Integration\Helper\PostgresConnectionConfig;
 use PDO;
 use PHPUnit\Framework\Attributes\CoversClass;
 
@@ -14,13 +15,7 @@ class PostgresPdoConnectionAdapterTest extends ConnectionAdapterTestCase {
 
     protected static function getConnectionAdapter() : ConnectionAdapter {
         return new PdoConnectionAdapter(
-            new ConnectionAdapterConfig(
-                'postgres',
-                'postgres',
-                5432,
-                'postgres',
-                'postgres'
-            ),
+            new PostgresConnectionConfig(),
             PdoDriver::Postgresql
         );
     }
@@ -30,7 +25,9 @@ protected function getExpectedUnderlyingConnectionClassName() : string {
     }
 
     protected function executeCountSql(string $table) : int {
-        return self::getUnderlyingConnection()->query('SELECT COUNT(*) AS "count" FROM my_table')
+        $connection = self::getUnderlyingConnection();
+        assert($connection instanceof PDO);
+        return $connection->query('SELECT COUNT(*) AS "count" FROM ' . $table)
             ->fetch(PDO::FETCH_ASSOC)['count'];
     }
 }

From 5690ca36aa299f5cb464abfc5446dc45a0033766 Mon Sep 17 00:00:00 2001
From: Charles Sprayberry <me@cspray.io>
Date: Thu, 2 Mar 2023 16:51:02 -0500
Subject: [PATCH 3/3] Check for interface, not class

---
 src/AmpPostgresConnectionAdapter.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/AmpPostgresConnectionAdapter.php b/src/AmpPostgresConnectionAdapter.php
index cf4d18b..3f45fe2 100644
--- a/src/AmpPostgresConnectionAdapter.php
+++ b/src/AmpPostgresConnectionAdapter.php
@@ -7,7 +7,7 @@
 use Cspray\DatabaseTestCase\Exception\MissingRequiredComposerPackage;
 use function Amp\Postgres\connect;
 
-if (! class_exists(PostgresLink::class)) {
+if (! interface_exists(PostgresLink::class)) {
     throw new MissingRequiredComposerPackage('You must install amphp/postgres to use ' . AmpPostgresConnectionAdapter::class);
 }