Level 70
@laracoft You better share your test and respective implementation.
Jan 15, 2024
14
Level 27
Failing test
Failed asserting that 2000.0000000000005 matches expected 2000.0.
->assertSet('balance', 2000.00) // part of Livewire::
- I took over a project with this failing test
- Both the
$actualand$expectedhave thegettype()of double and when inspected using XDebug, both are2000 - Because both are
2000, my expectation is forassetSet('balance', 2000.00)to pass without additional code - The offending line code is https://github.com/sebastianbergmann/comparator/blob/146dc7bb46c39d8d42bb0fd8cfdec588f0814f66/src/NumericComparator.php#L39-L44, where
$actual - $expectedis not 0 - Any idea what the issue might be?
Level 27
@tisuchi updated my OP
Level 122
the perils of floating point numbers
Level 104
You can specify a precision for the float/decimal comparison, e.g.
$this->assertEquals($expected, $actual, 0.001);
Level 27
Sorry, that would be hiding the problem deeper. I would like to know why 2000 is not equal to 2000.
Level 104
@laracoft because you are using floating point numbers for arithmetic, and that's why you get numbers like 2000.0000000000005
https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html
Level 27
Here is my logic:
- The tests only broke sometime in the last 3 years
- I also cannot reconcile the XDebug screenshot from my VSCode
- So, what can I do to make them pass without touching the code unnecessarily
Level 104
The tests only broke sometime in the last 3 years
Not particularly useful tests in that case!
I also cannot reconcile the XDebug screenshot from my VSCode
Nor can I. I don't know your code or how these values are arrived at.
So, what can I do to make them pass without touching the code unnecessarily
If you want to compare floating point numbers, I suggest you impose some delta which determines how precise the comparison should be. You can see the delta is very very small in your case!
Level 27
Would you know why XDebug is showing only 2000 instad of 2000.0000000000000x?
Level 104
@laracoft no, I don't use xdebug any longer.
Level 27
See my XDebug screenshot in the OP
Level 122
There is no point arguing, you cannot compare that two differently generated floating point numbers are exactly the same.
Your 1st mistake
->assertSet('balance', 2000.00)
NEVER use floating point for currency/monetary calculations
Level 27
Nobody is arguing here, I would like to know how to move forward by understanding why XDebug is hiding the problem or anything else. Overhauling the code is the last resort.
1 like
Level 104
Overhauling the code is the last resort
No-one suggested overhauling the code, just setting your expectations correctly!
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