PHP and unit testing assertions with decimals

Question

I have a method that returns a float like 1.234567890.I want to test that it really does so. However, it seems that this returned float has different precision on different platforms so how do I assert that the returned value is 1.23456789? If I just do:

$this->assertEqual(1.23456789, $float);

Then that might fail on some platforms where there is not enough precision.

Answer 1

So far it hasn't been mentioned that assertEquals supports comparing floats by offering a delta to specifiy precision:

$this->assertEquals(1.23456789, $float, '', 0.0001);

Thanks to @Antoine87 for pointing out: since phpunit 7.5 you should use assertEqualsWithDelta():

$this->assertEqualsWithDelta(1.23456789, $float, 0.0001);

Answer 2

As an update to @bernhard-wagner answer, you should now use assertEqualsWithDelta() since phpunit 7.5.

$this->assertEqualsWithDelta(1.23456789, $float, 0.0001);