Merge pull request #5 from Lewiscowles1986/random-interface

Added Injectable Random Source

Author: Lewiscowles1986

composer.json

@@ -2,7 +2,11 @@
     "name": "lewiscowles/ulid",
     "description": "Universally Unique Lexicographically Sortable Identifier ported to PHP",
     "type": "library",
+    "require": {
+        "php": ">=7.0"
+    }
     "require-dev": {
+        "ext-xdebug": "*",
         "phpunit/phpunit": "^5.4"
     },
     "license": "AGPL",

src/ulid.php

@@ -5,10 +5,19 @@
 final class Ulid {
     const ENCODING = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
     const ENCODING_LENGTH = 32;
+    protected $random_float_src;
+    
+    public function __construct(RandomFloatInterface $rf){
+        $this->random_float_src = $rf;
+    }
 
     public function get()
     {
-        return $this->encodeTime($this->getTime(), 10) . $this->encodeRandom(16);
+        return sprintf(
+            "%s%s",
+            $this->encodeTime($this->getTime(), 10),
+            $this->encodeRandom(16)
+        );
     }
 
     private function encodeTime(int $time, int $length) : string
@@ -28,20 +37,34 @@ private function encodeRandom(int $length) : string
     {
         $out = '';
         while($length > 0) {
-            $rand = intval(floor(self::ENCODING_LENGTH * $this->getRand()));
+            $rand = intval(
+                floor(
+                    self::ENCODING_LENGTH
+                    *
+                    $this->random_float_src->generate()
+                )
+            );
             $out = self::ENCODING[$rand] . $out;
             $length--;
         }
         return $out;
     }
 
-    private function getRand() : float
-    {
-        return lcg_value();
-    }
-    
     private function getTime() : int
     {
         return time();
     }
 }
+
+interface RandomFloatInterface {
+    public function generate() : float;
+}
+
+class LcgRandomGenerator implements RandomFloatInterface {
+    
+    public function __construct() { }
+    
+    public function generate() : float {
+        return lcg_value();
+    }
+}

tests/BaseTest.php

@@ -4,6 +4,7 @@
 require_once __DIR__.'/../src/ulid.php';
 
 use lewiscowles\core\Ulid;
+use lewiscowles\core\LcgRandomGenerator;
 
 use PHPUnit\Framework\TestCase;
 
@@ -14,12 +15,16 @@ class BaseTest extends TestCase
 
     public function setup()
     {
-        $this->ulid = new Ulid();
+        $this->ulid = new Ulid($this->getLcgRandom());
+    }
+
+    public function getLcgRandom() {
+        return new LcgRandomGenerator();
     }
 
     public function testRandIsBetween1and0()
     {
-        $rand = $this->invokeMethod($this->ulid, 'getRand');
+        $rand = $this->getLcgRandom()->generate();
         $this->assertTrue( $rand > 0 && $rand < 1 );
     }