Fix dataproviders in tests

Author: danmichaelo

tests/CollectionTest.php

@@ -35,7 +35,7 @@ public function testExceptionOnInvalidEncoding()
      *
      * @return array
      */
-    public function mrcFiles()
+    public static function mrcFiles()
     {
         return [
             ['sandburg.mrc', 1],        // Single binary MARC file
@@ -48,7 +48,7 @@ public function mrcFiles()
      *
      * @return array
      */
-    public function xmlFiles()
+    public static function xmlFiles()
     {
         return [
             ['oaipmh-bibsys.xml', 89],  // Records encapsulated in OAI-PMH response
@@ -86,7 +86,7 @@ public function testCollectionFromFile($filename, $expected)
      */
     public function testInitializeFromSimpleXmlElement($filename, $expected)
     {
-        $el = simplexml_load_file($this->pathTo($filename));
+        $el = simplexml_load_file(self::pathTo($filename));
 
         $collection = Collection::fromSimpleXMLElement($el);
 

tests/ExamplesTest.php

@@ -26,9 +26,9 @@ public function testExample($filename)
         }
     }
 
-    public function exampleDataProvider()
+    public static function exampleDataProvider()
     {
-        foreach (glob($this->pathTo('examples/*.xml')) as $filename) {
+        foreach (glob(self::pathTo('examples/*.xml')) as $filename) {
             yield [$filename];
         }
     }

tests/RecordTest.php

@@ -71,13 +71,13 @@ public function testExampleWithCustomPrefix()
 
     public function testBinaryMarc()
     {
-        $record = Record::fromFile($this->pathTo('binary-marc.mrc'));
+        $record = Record::fromFile(self::pathTo('binary-marc.mrc'));
         $this->assertInstanceOf(Record::class, $record);
     }
 
     public function testThatFieldObjectsAreReturned()
     {
-        $record = Record::fromFile($this->pathTo('binary-marc.mrc'));
+        $record = Record::fromFile(self::pathTo('binary-marc.mrc'));
         $this->assertInstanceOf(Field::class, $record->getField('020'));
         $this->assertInstanceOf(Field::class, $record->getFields('020')[0]);
     }

tests/TestCase.php

@@ -7,14 +7,14 @@
 
 class TestCase extends \PHPUnit\Framework\TestCase
 {
-    protected function pathTo($filename)
+    protected static function pathTo($filename)
     {
         return __DIR__ . '/data/' . $filename;
     }
 
     protected function getTestCollection($filename)
     {
-        return Collection::fromFile($this->pathTo($filename));
+        return Collection::fromFile(self::pathTo($filename));
     }
 
     protected function getNthrecord($filename, $n)