Add test (WIP with asserNotSame)

Author: mvorisek

tests/Persistence/SqlTest.php

@@ -7,6 +7,7 @@
 use Atk4\Data\Exception;
 use Atk4\Data\Model;
 use Atk4\Data\Schema\TestCase;
+use Atk4\Data\Persistence\Sql\Expression;
 
 class SqlTest extends TestCase
 {
@@ -213,9 +214,6 @@ public function testPersistenceDelete(): void
         $this->assertSame('Smith', $m2->get('surname'));
     }
 
-    /**
-     * Test export.
-     */
     public function testExport(): void
     {
         $this->setDb([
@@ -239,4 +237,38 @@ public function testExport(): void
             ['surname' => 'Jones'],
         ], $m->export(['surname']));
     }
+
+    public function testSameRowFieldStability(): void
+    {
+        $this->setDb([
+            'user' => [
+                1 => ['name' => 'John', 'surname' => 'Smith'],
+                2 => ['name' => 'Sarah', 'surname' => 'Jones'],
+            ],
+        ]);
+
+        $m = new Model($this->db, ['table' => 'user']);
+        $m->addField('name');
+        $m->addField('surname');
+        $m->addExpression(
+            'rand',
+            [
+                'sqlite' => 'random()',
+                'mysql' => 'rand()',
+                'postgresql' => 'random()',
+                'mssql' => 'rand()',
+                'oracle' => 'dbms_random.random',
+            ][$this->c->getDatabasePlatform()->getName()]
+        );
+        $m->addExpression('rand2', new Expression('([] + 1) - 1', [$m->getField('rand')]));
+        $m->setOnlyFields(['rand', 'rand2']);
+
+        $export = $m->export();
+        $this->assertSame([0, 1], array_keys($export));
+        $randRow0 = $export[0]['rand'];
+        $randRow1 = $export[1]['rand'];
+        $this->assertNotSame($randRow0, $randRow1);
+        $this->assertNotSame($randRow0, $export[0]['rand2']); // TODO assertSame
+        $this->assertNotSame($randRow0, $export[1]['rand2']);
+    }
 }