start to add ability to merge tunes

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

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

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Created by PhpStorm.
+ * User: richard
+ * Date: 06/05/18
+ * Time: 8:28 AM
+ */
+
+use XaiCorp\AbcParser\Domain\Core\TuneAttributeArrayBuilder;
+use XaiCorp\AbcParser\Domain\Atoms\UnsignedIntegerAtom;
+use XaiCorp\AbcParser\Domain\Core\Tune;
+
+class TuneAttributeArrayBuilderTest extends \Codeception\Test\Unit
+{
+
+    public function testSetIndex()
+    {
+        $index = new UnsignedIntegerAtom('14');
+        $builder = new TuneAttributeArrayBuilder();
+
+        $tune = $builder->setIndex($index)->getTune();
+
+        $this->assertInstanceOf(Tune::class, $tune);
+        $this->assertEquals($index->getValue(), $tune->getIndex());
+    }
+
+    public function testAppendMusic()
+    {
+        $music = new \Enzyme\Axiom\Atoms\StringAtom('Abcd|');
+        $builder = new TuneAttributeArrayBuilder();
+
+        $tune = $builder->appendMusic($music)->getTune();
+
+        $this->assertInstanceOf(Tune::class, $tune);
+        $this->assertEquals($music->getValue(), trim($tune->getMusic()));
+    }
+}