Adding interpolate test

src/LogFormat.php

@@ -32,7 +32,7 @@ public function create($level, $message, array $context = [])
             $message .= "\n".print_r($context, true);
         }
 
-        return $this->interpolate($message);
+        return $this->interpolate($message, $context);
     }
 
     /**

tests/InterpolateTest.php

@@ -0,0 +1,31 @@
+<?php
+
+use League\Flysystem\Adapter\Local;
+use League\Flysystem\Filesystem;
+use wappr\Logger;
+
+class InterpolateTest extends PHPUnit_Framework_TestCase
+{
+    public function testInterpolate()
+    {
+        $adapter = new Local(dirname(__DIR__).'/storage/logs/');
+        $filesystem = new Filesystem($adapter);
+        $logger = new Logger($filesystem, Psr\Log\LogLevel::INFO);
+
+        $values = [
+            'animal' => 'cat',
+        ];
+
+        $logger->info('A horse is a {animal}.', $values);
+
+        $logs = $filesystem->read(date('Y-m-d').'.log'); // read the logs into a string
+
+        $containsCat = false;
+
+        if (strpos($logs, 'cat') !== false) {
+            $containsCat = true;
+        }
+
+        $this->assertTrue($containsCat);
+    }
+}