diff --git a/src/Symfony/Component/Notifier/Bridge/Sinch/SinchTransportFactory.php b/src/Symfony/Component/Notifier/Bridge/Sinch/SinchTransportFactory.php
index 0dc36e196d..0fb16d4101 100644
--- a/src/Symfony/Component/Notifier/Bridge/Sinch/SinchTransportFactory.php
+++ b/src/Symfony/Component/Notifier/Bridge/Sinch/SinchTransportFactory.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Notifier\Bridge\Sinch;
 
+use Symfony\Component\Notifier\Exception\IncompleteDsnException;
 use Symfony\Component\Notifier\Exception\UnsupportedSchemeException;
 use Symfony\Component\Notifier\Transport\AbstractTransportFactory;
 use Symfony\Component\Notifier\Transport\Dsn;
@@ -26,17 +27,23 @@ final class SinchTransportFactory extends AbstractTransportFactory
     public function create(Dsn $dsn): TransportInterface
     {
         $scheme = $dsn->getScheme();
+
+        if ('sinch' !== $scheme) {
+            throw new UnsupportedSchemeException($dsn, 'sinch', $this->getSupportedSchemes());
+        }
+
         $accountSid = $this->getUser($dsn);
         $authToken = $this->getPassword($dsn);
         $from = $dsn->getOption('from');
+
+        if (!$from) {
+            throw new IncompleteDsnException('Missing from.', $dsn->getOriginalDsn());
+        }
+
         $host = 'default' === $dsn->getHost() ? null : $dsn->getHost();
         $port = $dsn->getPort();
 
-        if ('sinch' === $scheme) {
-            return (new SinchTransport($accountSid, $authToken, $from, $this->client, $this->dispatcher))->setHost($host)->setPort($port);
-        }
-
-        throw new UnsupportedSchemeException($dsn, 'sinch', $this->getSupportedSchemes());
+        return (new SinchTransport($accountSid, $authToken, $from, $this->client, $this->dispatcher))->setHost($host)->setPort($port);
     }
 
     protected function getSupportedSchemes(): array
diff --git a/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportFactoryTest.php b/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportFactoryTest.php
new file mode 100644
index 0000000000..72e59b93a0
--- /dev/null
+++ b/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportFactoryTest.php
@@ -0,0 +1,83 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Notifier\Bridge\Sinch\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Notifier\Bridge\Sinch\SinchTransportFactory;
+use Symfony\Component\Notifier\Exception\IncompleteDsnException;
+use Symfony\Component\Notifier\Exception\UnsupportedSchemeException;
+use Symfony\Component\Notifier\Transport\Dsn;
+
+final class SinchTransportFactoryTest extends TestCase
+{
+    public function testCreateWithDsn()
+    {
+        $factory = $this->createFactory();
+
+        $dsn = 'sinch://accountSid:authToken@default?from=0611223344';
+        $transport = $factory->create(Dsn::fromString($dsn));
+        $transport->setHost('host.test');
+
+        $this->assertSame('sinch://host.test?from=0611223344', (string) $transport);
+    }
+
+    public function testCreateWithMissingOptionFromThrowsIncompleteDsnException()
+    {
+        $factory = $this->createFactory();
+
+        $this->expectException(IncompleteDsnException::class);
+
+        $dsnIncomplete = 'sinch://accountSid:authToken@default';
+        $factory->create(Dsn::fromString($dsnIncomplete));
+    }
+
+    public function testSupportsReturnsTrueWithSupportedScheme()
+    {
+        $factory = $this->createFactory();
+
+        $dsn = 'sinch://accountSid:authToken@default?from=0611223344';
+        $this->assertTrue($factory->supports(Dsn::fromString($dsn)));
+    }
+
+    public function testSupportsReturnsFalseWithUnsupportedScheme()
+    {
+        $factory = $this->createFactory();
+
+        $dsnUnsupported = 'sinnnnch://accountSid:authToken@default?from=0611223344';
+        $this->assertFalse($factory->supports(Dsn::fromString($dsnUnsupported)));
+    }
+
+    public function testUnsupportedSchemeThrowsUnsupportedSchemeException()
+    {
+        $factory = $this->createFactory();
+
+        $this->expectException(UnsupportedSchemeException::class);
+
+        $dsnUnsupported = 'sinnnnch://accountSid:authToken@default?from=0611223344';
+        $factory->create(Dsn::fromString($dsnUnsupported));
+    }
+
+    public function testUnsupportedSchemeThrowsUnsupportedSchemeExceptionEvenIfRequiredOptionIsMissing()
+    {
+        $factory = $this->createFactory();
+
+        $this->expectException(UnsupportedSchemeException::class);
+
+        // unsupported scheme and missing "from" option
+        $factory->create(Dsn::fromString('sinnnnch://accountSid:authToken@default'));
+    }
+
+    private function createFactory(): SinchTransportFactory
+    {
+        return new SinchTransportFactory();
+    }
+}
diff --git a/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportTest.php b/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportTest.php
new file mode 100644
index 0000000000..7f7ea4208c
--- /dev/null
+++ b/src/Symfony/Component/Notifier/Bridge/Sinch/Tests/SinchTransportTest.php
@@ -0,0 +1,51 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Notifier\Bridge\Sinch\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Notifier\Bridge\Sinch\SinchTransport;
+use Symfony\Component\Notifier\Exception\LogicException;
+use Symfony\Component\Notifier\Message\MessageInterface;
+use Symfony\Component\Notifier\Message\SmsMessage;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
+
+final class SinchTransportTest extends TestCase
+{
+    public function testToStringContainsProperties()
+    {
+        $transport = $this->createTransport();
+
+        $this->assertSame('sinch://host.test?from=sender', (string) $transport);
+    }
+
+    public function testSupportsMessageInterface()
+    {
+        $transport = $this->createTransport();
+
+        $this->assertTrue($transport->supports(new SmsMessage('0611223344', 'Hello!')));
+        $this->assertFalse($transport->supports($this->createMock(MessageInterface::class)));
+    }
+
+    public function testSendNonSmsMessageThrowsException()
+    {
+        $transport = $this->createTransport();
+
+        $this->expectException(LogicException::class);
+
+        $transport->send($this->createMock(MessageInterface::class));
+    }
+
+    private function createTransport(): SinchTransport
+    {
+        return (new SinchTransport('accountSid', 'authToken', 'sender', $this->createMock(HttpClientInterface::class)))->setHost('host.test');
+    }
+}
diff --git a/src/Symfony/Component/Notifier/Bridge/Sinch/composer.json b/src/Symfony/Component/Notifier/Bridge/Sinch/composer.json
index 1030cc2611..360139e6b8 100644
--- a/src/Symfony/Component/Notifier/Bridge/Sinch/composer.json
+++ b/src/Symfony/Component/Notifier/Bridge/Sinch/composer.json
@@ -19,7 +19,7 @@
         "php": ">=7.2.5",
         "ext-json": "*",
         "symfony/http-client": "^4.3|^5.0",
-        "symfony/notifier": "^5.0,<5.2"
+        "symfony/notifier": "~5.1.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Notifier\\Bridge\\Sinch\\": "" },
diff --git a/src/Symfony/Component/Notifier/Bridge/Sinch/phpunit.xml.dist b/src/Symfony/Component/Notifier/Bridge/Sinch/phpunit.xml.dist
new file mode 100644
index 0000000000..298663e372
--- /dev/null
+++ b/src/Symfony/Component/Notifier/Bridge/Sinch/phpunit.xml.dist
@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.2/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Symfony Sinch Notifier Bridge Test Suite">
+            <directory>./Tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./</directory>
+            <exclude>
+                <directory>./Resources</directory>
+                <directory>./Tests</directory>
+                <directory>./vendor</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+</phpunit>