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.

Noncompliant Code Example

assertEqual($a, $a); // Noncompliant
assertSame($a, $a); // Noncompliant
assertNotEqual($a, $a); // Noncompliant
assertNotSame($a, $a); // Noncompliant

Compliant Solution

assertEqual($expected, $a);
assertSame($expected, $a);
assertNotEqual($expected, $a);
assertNotSame($expected, $a);