setup approval tests with golden master using scalatest

scala/src/test/scala/com/gildedrose/GildedRoseApprovalTest.scala

@@ -0,0 +1,32 @@
+package com.gildedrose
+
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+import java.io.{File, FileOutputStream}
+import scala.io.Source
+
+class GildedRoseApprovalTest extends AnyFlatSpec with Matchers {
+  it should "return the result of the golden master" in {
+    val fileWithTestResult = new File("approvaltests/gildedrose.testresult.txt")
+    val outputStream       = new FileOutputStream(fileWithTestResult)
+    Console.withOut(outputStream) {
+
+      TexttestFixture.main(Array("30"))
+    }
+
+    val approvedFile          = "approvaltests/gildedrose.approved.txt"
+    val sourceForTestResults  = Source.fromFile(fileWithTestResult)
+    val sourceForApprovedFile = Source.fromFile(approvedFile)
+
+    val resultingOutput =
+      try sourceForTestResults.getLines().toVector
+      finally sourceForTestResults.close()
+    val approvedOutput =
+      try sourceForApprovedFile.getLines().toVector
+      finally sourceForTestResults.close()
+
+    resultingOutput should equal(approvedOutput)
+  }
+
+}