Fix crash when 250 is missing

Author: danmichaelo

src/Fields/Edition.php

@@ -8,7 +8,7 @@ class Edition extends Field implements FieldInterface
 {
     public static function get(Record $record)
     {
-        foreach ($record->query('250') as $field) {
+        foreach ($record->query('250{$a}') as $field) {
             return new static($field->getField());
         }
     }

tests/EditionTest.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Tests;
+
+use Scriptotek\Marc\Fields\Field;
+use Scriptotek\Marc\Record;
+use Scriptotek\Marc\QueryResult;
+
+class EditionTest extends TestCase
+{
+    protected $record;
+
+    public function testSimple250()
+    {
+        $record = Record::fromString('<?xml version="1.0" encoding="UTF-8" ?>
+          <record xmlns="http://www.loc.gov/MARC21/slim">
+            <leader>99999cam a2299999 u 4500</leader>
+            <controlfield tag="001">98218834x</controlfield>
+            <datafield tag="250" ind1=" " ind2=" ">
+              <subfield code="a">2nd ed. </subfield>
+            </datafield>
+          </record>');
+
+        $this->assertEquals('2nd ed.', $record->edition);
+    }
+
+    public function testMissingA()
+    {
+        $record = Record::fromString('<?xml version="1.0" encoding="UTF-8" ?>
+          <record xmlns="http://www.loc.gov/MARC21/slim">
+            <leader>99999cam a2299999 u 4500</leader>
+            <controlfield tag="001">98218834x</controlfield>
+            <datafield tag="250" ind1=" " ind2=" ">
+              <subfield code="b">2nd ed. </subfield>
+            </datafield>
+          </record>');
+
+        $this->assertNull($record->edition);
+    }
+}