Revert "[tests] update test case on unique method"

This reverts commit ea567b2.

Author: dsavina

tests/FluidColumnOptionsTest.php

@@ -26,8 +26,8 @@ public function testOptions()
         $columnOptions->notNull();
         $this->assertSame(true, $dbalColumn->getNotnull());
 
-        $columnOptions->unique('unique_foo');
-        $this->assertSame(true, $posts->getDbalTable()->getIndex('unique_foo')->isUnique());
+        $columnOptions->unique();
+        $this->assertSame(true, $dbalColumn->getCustomSchemaOption('unique'));
 
         $columnOptions->comment('foo');
         $this->assertSame('foo', $dbalColumn->getComment());