Implement LocalTime::fromDateTime()

src/LocalTime.php

@@ -75,10 +75,10 @@ private function __construct(int $hour, int $minute, int $second, int $nano)
     }
 
     /**
-     * @param int $hour
-     * @param int $minute
-     * @param int $second
-     * @param int $nano
+     * @param int $hour   The hour, from 0 to 23.
+     * @param int $minute The minute, from 0 to 59.
+     * @param int $second The second, from 0 to 59.
+     * @param int $nano   The nano-of-second, from 0 to 999,999,999.
      *
      * @return LocalTime
      *
@@ -157,6 +157,23 @@ public static function parse(string $text, DateTimeParser $parser = null) : Loca
         return LocalTime::from($parser->parse($text));
     }
 
+    /**
+     * Creates a LocalTime from a native DateTime object.
+     *
+     * @param \DateTimeInterface $dateTime
+     *
+     * @return LocalTime
+     */
+    public static function fromDateTime(\DateTimeInterface $dateTime) : LocalTime
+    {
+        return new LocalTime(
+            (int) $dateTime->format('G'),
+            (int) $dateTime->format('i'),
+            (int) $dateTime->format('s'),
+            1000 * (int) $dateTime->format('u')
+        );
+    }
+
     /**
      * Returns the current local time in the given time-zone, according to the given clock.
      *

tests/LocalTimeTest.php

@@ -176,6 +176,12 @@ public function providerParseInvalidStringThrowsException() : array
         ];
     }
 
+    public function testFromDateTime()
+    {
+        $dateTime = new \DateTime('2018-07-21 14:09:10.23456');
+        $this->assertLocalTimeIs(14, 9, 10, 234560000, LocalTime::fromDateTime($dateTime));
+    }
+
     /**
      * @dataProvider providerNow
      *