diff --git a/composer.json b/composer.json
index 2c0c81e..d9a826c 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,6 @@
     },
     "require-dev": {
         "amphp/php-cs-fixer-config": "^2",
-        "amphp/phpunit-util": "^3",
         "phpunit/phpunit": "^9",
         "psalm/phar": "^5.4"
     },
diff --git a/src/SqlConfig.php b/src/SqlConfig.php
index 0312d10..d6b77ba 100644
--- a/src/SqlConfig.php
+++ b/src/SqlConfig.php
@@ -26,9 +26,9 @@ abstract class SqlConfig
      * Parses a connection string into an array of keys and values given.
      *
      * @param string $connectionString Connection string, e.g., "hostname=localhost username=sql password=default"
-     * @param string[] $keymap Map of alternative key names to canonical key names.
+     * @param array<non-empty-string, non-empty-string> $keymap Map of alternative key names to canonical key names.
      *
-     * @return string[]
+     * @return array<non-empty-string, string>
      */
     protected static function parseConnectionString(string $connectionString, array $keymap = self::KEY_MAP): array
     {
@@ -42,18 +42,17 @@ abstract class SqlConfig
 
         foreach ($params as $param) {
             /** @psalm-suppress PossiblyInvalidArgument */
-            [$key, $value] = \array_map("trim", \explode("=", $param, 2) + [1 => ""]);
-
-            if (isset($keymap[$key])) {
-                $key = $keymap[$key];
+            [$key, $value] = \array_map(\trim(...), \explode("=", $param, 2) + [1 => ""]);
+            if ($key === '') {
+                throw new \ValueError("Empty key name in connection string");
             }
 
-            $values[$key] = $value;
+            $values[$keymap[$key] ?? $key] = $value;
         }
 
-        if (\preg_match('/^(.+):(\d{1,5})$/', $values["host"] ?? "", $matches)) {
-            $values["host"] = $matches[1];
-            $values["port"] = $matches[2];
+        if (\preg_match('/^(?<host>.+):(?<port>\d{1,5})$/', $values["host"] ?? "", $matches)) {
+            $values["host"] = $matches["host"];
+            $values["port"] = $matches["port"];
         }
 
         return $values;
diff --git a/test/QueryErrorTest.php b/test/QueryErrorTest.php
index 8721310..bcd61cf 100644
--- a/test/QueryErrorTest.php
+++ b/test/QueryErrorTest.php
@@ -2,10 +2,10 @@
 
 namespace Amp\Sql\Test;
 
-use Amp\PHPUnit\AsyncTestCase;
 use Amp\Sql\QueryError;
+use PHPUnit\Framework\TestCase;
 
-class QueryErrorTest extends AsyncTestCase
+class QueryErrorTest extends TestCase
 {
     /**
      * @test
@@ -14,7 +14,7 @@ class QueryErrorTest extends AsyncTestCase
     {
         $error = new QueryError('error', 'SELECT * FROM foo');
 
-        $this->assertSame('SELECT * FROM foo', $error->getQuery());
-        $this->assertStringStartsWith("Amp\Sql\QueryError: error\nCurrent query was SELECT * FROM foo", (string) $error);
+        self::assertSame('SELECT * FROM foo', $error->getQuery());
+        self::assertStringStartsWith("Amp\Sql\QueryError: error\nCurrent query was SELECT * FROM foo", (string) $error);
     }
 }
diff --git a/test/SqlConfigTest.php b/test/SqlConfigTest.php
new file mode 100644
index 0000000..5e80860
--- /dev/null
+++ b/test/SqlConfigTest.php
@@ -0,0 +1,67 @@
+<?php declare(strict_types=1);
+
+namespace Amp\Sql\Test;
+
+use Amp\Sql\SqlConfig;
+use PHPUnit\Framework\TestCase;
+
+class SqlConfigTest extends TestCase
+{
+    private function createConfigFromString(string $connectionString): SqlConfig
+    {
+        return new class($connectionString) extends SqlConfig {
+            public function __construct(string $connectionString)
+            {
+                $parts = self::parseConnectionString($connectionString);
+
+                parent::__construct(
+                    host: $parts["host"] ?? '',
+                    port: (int) ($parts["port"] ?? 0),
+                    user: $parts["user"] ?? "",
+                    password: $parts["password"] ?? "",
+                    database: $parts["db"] ?? "",
+                );
+            }
+        };
+    }
+
+    public function testPortInHost(): void
+    {
+        $config = $this->createConfigFromString("host=localhost:5432 user=user database=test");
+
+        self::assertSame("localhost", $config->getHost());
+        self::assertSame(5432, $config->getPort());
+        self::assertSame("user", $config->getUser());
+        self::assertSame("", $config->getPassword());
+        self::assertSame("test", $config->getDatabase());
+    }
+
+    public function testBasicSyntax(): void
+    {
+        $config = $this->createConfigFromString("host=localhost port=5432 user=user pass=test db=test");
+
+        self::assertSame("localhost", $config->getHost());
+        self::assertSame(5432, $config->getPort());
+        self::assertSame("user", $config->getUser());
+        self::assertSame("test", $config->getPassword());
+        self::assertSame("test", $config->getDatabase());
+    }
+
+    public function testAlternativeSyntax(): void
+    {
+        $config = $this->createConfigFromString("host=localhost;port=3306;user=user;password=test;db=test");
+
+        self::assertSame("localhost", $config->getHost());
+        self::assertSame(3306, $config->getPort());
+        self::assertSame("user", $config->getUser());
+        self::assertSame("test", $config->getPassword());
+        self::assertSame("test", $config->getDatabase());
+    }
+
+    public function testInvalidString(): void
+    {
+        $this->expectException(\ValueError::class);
+        $this->expectExceptionMessage("Empty key name in connection string");
+        $this->createConfigFromString("invalid =connection string");
+    }
+}