feature #32463 [VarDumper] Allow to configure VarDumperTestTrait casters & flags (ogizanagi)

This PR was merged into the 4.4 branch.

Discussion
----------

[VarDumper] Allow to configure VarDumperTestTrait casters & flags

| Q             | A
| ------------- | ---
| Branch?       | 4.4 <!-- see below -->
| Bug fix?      | no
| New feature?  | yes <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | N/A   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | TODO: showcase using `setUpVarDumper` in `setUp` or in specific test cases accordingly to the use-case. `tearDownVarDumper` is automatically called after each test case.

The VarDumper component is a great tool in tests to assert objects states.
The ability to register custom casters on need is a nice way to control only the fields you're expecting, or a way to write concise test cases.
Hence this feature allowing to configure casters specifically per test class/case.

Commits
-------

613dbb2 [VarDumper] Allow to configure VarDumperTestTrait casters & flags

Author: nicolas-grekas

src/Symfony/Component/VarDumper/Test/VarDumperTestTrait.php

@@ -19,6 +19,29 @@
  */
 trait VarDumperTestTrait
 {
+    /**
+     * @internal
+     */
+    private $varDumperConfig = [
+        'casters' => [],
+        'flags' => null,
+    ];
+
+    protected function setUpVarDumper(array $casters, int $flags = null): void
+    {
+        $this->varDumperConfig['casters'] = $casters;
+        $this->varDumperConfig['flags'] = $flags;
+    }
+
+    /**
+     * @after
+     */
+    protected function tearDownVarDumper(): void
+    {
+        $this->varDumperConfig['casters'] = [];
+        $this->varDumperConfig['flags'] = null;
+    }
+
     public function assertDumpEquals($expected, $data, $filter = 0, $message = '')
     {
         $this->assertSame($this->prepareExpectation($expected, $filter), $this->getDump($data, null, $filter), $message);
@@ -31,11 +54,14 @@ public function assertDumpMatchesFormat($expected, $data, $filter = 0, $message
 
     protected function getDump($data, $key = null, $filter = 0)
     {
-        $flags = getenv('DUMP_LIGHT_ARRAY') ? CliDumper::DUMP_LIGHT_ARRAY : 0;
-        $flags |= getenv('DUMP_STRING_LENGTH') ? CliDumper::DUMP_STRING_LENGTH : 0;
-        $flags |= getenv('DUMP_COMMA_SEPARATOR') ? CliDumper::DUMP_COMMA_SEPARATOR : 0;
+        if (null === $flags = $this->varDumperConfig['flags']) {
+            $flags = getenv('DUMP_LIGHT_ARRAY') ? CliDumper::DUMP_LIGHT_ARRAY : 0;
+            $flags |= getenv('DUMP_STRING_LENGTH') ? CliDumper::DUMP_STRING_LENGTH : 0;
+            $flags |= getenv('DUMP_COMMA_SEPARATOR') ? CliDumper::DUMP_COMMA_SEPARATOR : 0;
+        }
 
         $cloner = new VarCloner();
+        $cloner->addCasters($this->varDumperConfig['casters']);
         $cloner->setMaxItems(-1);
         $dumper = new CliDumper(null, null, $flags);
         $dumper->setColors(false);

src/Symfony/Component/VarDumper/Tests/Test/VarDumperTestTraitTest.php

@@ -12,6 +12,8 @@
 namespace Symfony\Component\VarDumper\Tests\Test;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\VarDumper\Cloner\Stub;
+use Symfony\Component\VarDumper\Dumper\CliDumper;
 use Symfony\Component\VarDumper\Test\VarDumperTestTrait;
 
 class VarDumperTestTraitTest extends TestCase
@@ -43,4 +45,34 @@ public function testAllowsNonScalarExpectation()
     {
         $this->assertDumpEquals(new \ArrayObject(['bim' => 'bam']), new \ArrayObject(['bim' => 'bam']));
     }
+
+    public function testItCanBeConfigured()
+    {
+        $this->setUpVarDumper($casters = [
+            \DateTimeInterface::class => static function (\DateTimeInterface $date, array $a, Stub $stub): array {
+                $stub->class = 'DateTime';
+
+                return ['date' => $date->format('d/m/Y')];
+            },
+        ], CliDumper::DUMP_LIGHT_ARRAY | CliDumper::DUMP_COMMA_SEPARATOR);
+
+        $this->assertSame(CliDumper::DUMP_LIGHT_ARRAY | CliDumper::DUMP_COMMA_SEPARATOR, $this->varDumperConfig['flags']);
+        $this->assertSame($casters, $this->varDumperConfig['casters']);
+
+        $this->assertDumpEquals(<<<DUMP
+[
+  1,
+  2,
+  DateTime {
+    +date: "09/07/2019"
+  }
+]
+DUMP
+        , [1, 2, new \DateTime('2019-07-09T0:00:00+00:00')]);
+
+        $this->tearDownVarDumper();
+
+        $this->assertNull($this->varDumperConfig['flags']);
+        $this->assertSame([], $this->varDumperConfig['casters']);
+    }
 }