Why is this an issue?

The standard PHPUnit assertion methods such as __assertEquals__, expect the first argument to be the expected value and the second argument to be the actual value.

What is the potential impact?

Having the expected value and the actual value in the wrong order will not alter the outcome of tests, (succeed/fail when it should) but the error messages will contain misleading information.

This rule raises an issue when the actual argument to an assertions library method is a hard-coded value and the expected argument is not.

How to fix it

You should provide the assertion methods with a hard-coded value as the expected value, while the actual value of the assertion should derive from the portion of code that you want to test.

Code examples

Noncompliant code example

self::assertEquals($runner.getExitCode(), 0, "Unexpected exit code"); // Noncompliant; Failed asserting that 0 matches expected 3. Expected :3 Actual :0.

Compliant solution

self::assertEquals(0, $runner.getExitCode(), "Unexpected exit code");