Add RetryConnection test cases

tests/RetryConnectionTest.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace ipl\Tests\Sql;
+
+use Exception;
+use ipl\Sql\RetryConnection;
+
+class RetryConnectionTest extends \PHPUnit\Framework\TestCase
+{
+    public function testIsRetryable()
+    {
+        $db = $this->getConnection();
+
+        $this->assertTrue($db::isRetryable(new Exception('SQLState: Connection refused by the server')));
+        $this->assertTrue($db::isRetryable(new Exception('SQLState: Error writing data to the connection')));
+        $this->assertTrue($db::isRetryable(new Exception('SQLState: No such file or directory found')));
+
+        $this->assertFalse($db::isRetryable(new Exception('SQLState: Cannot start transaction')));
+        $this->assertFalse($db::isRetryable(new Exception('Cannot establish the connection to SQL server')));
+        $this->assertFalse($db::isRetryable(new Exception('Fatal error encountered during command execution')));
+    }
+
+    public function testExecutionRetriesGivesUpAfterMaxRetries()
+    {
+        $this->expectException(Exception::class);
+        $this->expectExceptionMessage('SQLSTATE[HY000] [2002] No such file or directory');
+
+        $this->getConnection(2)->transaction(function () {
+        });
+    }
+
+    protected function getConnection(int $retries = 1): RetryConnection
+    {
+        return new RetryConnection([
+            'db'      => 'mysql',
+            'dbname'  => 'foo',
+        ], $retries);
+    }
+}