assertEquals() hides contents of long strings

[mikkorantalainen]

Q	A
PHPUnit version	10.5.20
PHP version	8.1.2-1ubuntu2.17 (cli)
Installation Method	PHAR

Summary

When I have long strings in an array that's passed to assertEquals() and the values are not equal, the emitted failure message clips away important part of the string.

How to reproduce

mkdir test && cd test
wget -O phpunit https://phar.phpunit.de/phpunit-10.phar
cat << 'EOF' > UnitTest.php
<?php
class UnitTest extends PHPUnit\Framework\TestCase
{
  public function testAssertingArrays()
  {
    $mock_testresult = array(
      0 => "Some short string",
      1 => "Some really long string that just keeps going and going and going but contains important clue HERE about why this whole test failed.",
    );
    $this->assertEquals($mock_testresult, array(), "Expected empty array but got non-empty array.");
  }
}
EOF
php phpunit UnitTest.php

Current behavior

PHPUnit 10.5.20 by Sebastian Bergmann and contributors.

Runtime:       PHP 8.1.2-1ubuntu2.17

F                                                                   1 / 1 (100%)

Time: 00:00.001, Memory: 24.79 MB

There was 1 failure:

1) UnitTest::testAssertingArrays
Expected empty array but got non-empty array.
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
-    0 => 'Some short string'
-    1 => 'Some really long string that ...ailed.'
 )

/home/user/test/UnitTest.php:10

FAILURES!
Tests: 1, Assertions: 1, Failures: 1

Expected behavior

Otherwise same but the array offset 1 should show enough of the string to also see the word "HERE".

Additional information

I can see the whole string if I run php phpunit --debug UnitTest.php instead but the output is so verbose otherwise that it's hard to read. I'd rather see normal output but the whole string, but I couldn't find any documented feature to turn off this kind of string clipping/shortening.

[hans-thomas]

@sebastianbergmann It's because of this block of code in the sebastian/exporter package.

Should we remove that condition to solve this?

[mfn]

Wow, it would be super useful to not have this clipping at all.

I've so many cases where I see the clipping where I realize my "expected" actually is wrong and it would just speed up things if I can copypaste it from that output and carry on.