Add PostgreSQL Support (#3)

Reviewed-on: #3

tests/integration/sqlite/CountTest.php

@@ -2,7 +2,7 @@
 
 namespace Test\Integration\SQLite;
 
-use BitBadger\PDODocument\{Count, Field};
+use BitBadger\PDODocument\{Count, DocumentException, Field};
 use PHPUnit\Framework\Attributes\TestDox;
 use PHPUnit\Framework\TestCase;
 
@@ -44,4 +44,17 @@ class CountTest extends TestCase
         $count = Count::byFields(ThrowawayDb::TABLE, [Field::BT('value', 'aardvark', 'apple')]);
         $this->assertEquals(1, $count, 'There should have been 1 matching document');
     }
+
+    public function testByContainsFails(): void
+    {
+        $this->expectException(DocumentException::class);
+        Count::byContains('', []);
+    }
+
+    #[TestDox('By JSON Path fails')]
+    public function testByJsonPathFails(): void
+    {
+        $this->expectException(DocumentException::class);
+        Count::byJsonPath('', '');
+    }
 }