Assertions comparing an object to itself are more likely to be bugs due to developer's carelessness.
This rule raises an issue when the actual expression matches the expected expression.
assertEqual($a, $a); // Noncompliant assertSame($a, $a); // Noncompliant assertNotEqual($a, $a); // Noncompliant assertNotSame($a, $a); // Noncompliant
assertEqual($expected, $a); assertSame($expected, $a); assertNotEqual($expected, $a); assertNotSame($expected, $a);