minor #23786 [VarDumper] Remove leading 0 in microseconds of date cas…

…ter (maidmaid)

This PR was merged into the 3.4 branch.

Discussion
----------

[VarDumper] Remove leading 0 in microseconds of date caster

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | /
| License       | MIT
| Doc PR        | /

It looks more like a [engineering notation](https://en.wikipedia.org/wiki/Engineering_notation). We can now better discern **milli**seconds and **micro**seconds.

```php
// before -> after
1.000000 -> 1.0
1.100000 -> 1.100
1.120000 -> 1.120
1.123000 -> 1.123
1.123400 -> 1.123400
1.123450 -> 1.123450
1.123456 -> 1.123456
```

Commits
-------

94956eb Remove leading 0 in ms of date caster

src/Symfony/Component/VarDumper/Caster/DateCaster.php

@@ -32,7 +32,7 @@ public static function castDateTime(\DateTimeInterface $d, array $a, Stub $stub,
         ;
 
         $a = array();
-        $a[$prefix.'date'] = new ConstStub($d->format('Y-m-d H:i:s.u '.($location ? 'e (P)' : 'P')), $title);
+        $a[$prefix.'date'] = new ConstStub($d->format('Y-m-d H:i:'.self::formatSeconds($d->format('s'), $d->format('u')).($location ? ' e (P)' : ' P')), $title);
 
         $stub->class .= $d->format(' @U');
 
@@ -59,7 +59,7 @@ private static function formatInterval(\DateInterval $i)
         ;
 
         if (\PHP_VERSION_ID >= 70100 && isset($i->f)) {
-            $format .= $i->h || $i->i || $i->s || $i->f ? '%H:%I:%S.%F' : '';
+            $format .= $i->h || $i->i || $i->s || $i->f ? '%H:%I:'.self::formatSeconds($i->s, $i->f) : '';
         } else {
             $format .= $i->h || $i->i || $i->s ? '%H:%I:%S' : '';
         }
@@ -79,4 +79,9 @@ public static function castTimeZone(\DateTimeZone $timeZone, array $a, Stub $stu
 
         return $filter & Caster::EXCLUDE_VERBOSE ? $z : $z + $a;
     }
+
+    private static function formatSeconds($s, $us)
+    {
+        return sprintf('%02d.%s', $s, 0 === ($len = strlen($t = rtrim($us, '0'))) ? '0' : ($len <= 3 ? str_pad($t, 3, '0') : $us));
+    }
 }

src/Symfony/Component/VarDumper/Tests/Caster/DateCasterTest.php

@@ -52,7 +52,7 @@ public function testCastDateTime()
 
         $xDump = <<<'EODUMP'
 array:1 [
-  "\x00~\x00date" => 2017-08-30 00:00:00.000000 Europe/Zurich (+02:00)
+  "\x00~\x00date" => 2017-08-30 00:00:00.0 Europe/Zurich (+02:00)
 ]
 EODUMP;
 
@@ -61,7 +61,7 @@ public function testCastDateTime()
         $xDump = <<<'EODUMP'
 Symfony\Component\VarDumper\Caster\ConstStub {
   +type: 1
-  +class: "2017-08-30 00:00:00.000000 Europe/Zurich (+02:00)"
+  +class: "2017-08-30 00:00:00.0 Europe/Zurich (+02:00)"
   +value: """
     Wednesday, August 30, 2017\n
     +%a from now\n
@@ -81,8 +81,15 @@ public function testCastDateTime()
     public function provideDateTimes()
     {
         return array(
-            array('2017-04-30 00:00:00.000000', 'Europe/Zurich', '2017-04-30 00:00:00.000000 Europe/Zurich (+02:00)'),
-            array('2017-04-30 00:00:00.000000', '+02:00', '2017-04-30 00:00:00.000000 +02:00'),
+            array('2017-04-30 00:00:00.000000', 'Europe/Zurich', '2017-04-30 00:00:00.0 Europe/Zurich (+02:00)'),
+            array('2017-04-30 00:00:00.000000', '+02:00', '2017-04-30 00:00:00.0 +02:00'),
+
+            array('2017-04-30 00:00:00.100000', '+02:00', '2017-04-30 00:00:00.100 +02:00'),
+            array('2017-04-30 00:00:00.120000', '+02:00', '2017-04-30 00:00:00.120 +02:00'),
+            array('2017-04-30 00:00:00.123000', '+02:00', '2017-04-30 00:00:00.123 +02:00'),
+            array('2017-04-30 00:00:00.123400', '+02:00', '2017-04-30 00:00:00.123400 +02:00'),
+            array('2017-04-30 00:00:00.123450', '+02:00', '2017-04-30 00:00:00.123450 +02:00'),
+            array('2017-04-30 00:00:00.123456', '+02:00', '2017-04-30 00:00:00.123456 +02:00'),
         );
     }
 
@@ -162,7 +169,7 @@ public function testCastInterval($intervalSpec, $invert, $xInterval, $xSeconds)
     public function provideIntervals()
     {
         $i = new \DateInterval('PT0S');
-        $ms = \PHP_VERSION_ID >= 70100 && isset($i->f) ? '.000000' : '';
+        $ms = \PHP_VERSION_ID >= 70100 && isset($i->f) ? '.0' : '';
 
         return array(
             array('PT0S', 0, '0s', '0s'),