start to add ability to merge tunes

started refactoring tune builders to use string type hint instead of StringAtom

tests/unit/AbcParser/Domain/Core/TuneTest.php

@@ -16,6 +16,7 @@ use XaiCorp\AbcParser\Domain\Core\Author;
 use XaiCorp\AbcParser\Domain\Core\Composer;
 use XaiCorp\AbcParser\Domain\Core\Tune;
 use XaiCorp\AbcParser\Domain\Core\Setting;
+use XaiCorp\AbcParser\Domain\Core\TuneAttributeArrayBuilder;
 
 class TuneTest extends \PHPUnit_Framework_TestCase
 {
@@ -28,17 +29,15 @@ class TuneTest extends \PHPUnit_Framework_TestCase
         $this->assertInstanceOf(Tune::class, $tune);
     }
 
-    public function testCanIntializeFromArray()
+    public function testCanInitializeFromArray()
     {
         $titles = ['Title'];
         $authors = ['Richard Morgan'];
 
-        $config = [
-            'Titles' => $titles,
-            'Authors' => $authors
-        ];
-
-        $tune = new Tune($config);
+        $tune = TuneAttributeArrayBuilder::create()
+            ->addTitle($titles[0])
+            ->addAuthor($authors[0])
+            ->getTune();
 
         $this->assertInstanceOf(Tune::class, $tune);
         $this->assertEquals($tune->getTitles(), $titles);
@@ -187,17 +186,21 @@ class TuneTest extends \PHPUnit_Framework_TestCase
 
     public function testMergeAddsExtraDataToTune()
     {
-        $targetTune = new Tune([
-            'titles' => ['target']
-        ]);
-        $sourceTune = new Tune([
-            'titles' => ['source']
-        ]);
+        $targetTune = TuneAttributeArrayBuilder::create()
+            ->addTitle('target')
+            ->getTune();
+
+        $sourceTune = TuneAttributeArrayBuilder::create()
+            ->addTitle('source')
+            ->getTune();
+
+        $expected = TuneAttributeArrayBuilder::create()
+            ->addTitle('target')
+            ->addTitle('source')
+            ->getTune($targetTune->identity());
 
         $result = $targetTune->merge($sourceTune);
 
-        $this->assertEquals(new Tune([
-            'titles' => ['target', 'source']
-        ]), $result);
+        $this->assertEquals($expected, $result);
     }
 }