Add test case.

Source/ID3TagEditor.swift

@@ -12,6 +12,7 @@ import Foundation
  */
 public class ID3TagEditor {
     private let id3TagParser: ID3TagParser
+    private let id3TagCreator: ID3TagCreator
     private let mp3FileReader: Mp3FileReader
     private let mp3FileWriter: Mp3FileWriter
     private let mp3WithID3TagBuilder: Mp3WithID3TagBuilder
@@ -21,9 +22,10 @@ public class ID3TagEditor {
      */
     public init() {
         self.id3TagParser = ID3TagParserFactory.make()
+        self.id3TagCreator = ID3TagCreatorFactory.make()
         self.mp3FileReader = Mp3FileReaderFactory.make()
         self.mp3FileWriter = Mp3FileWriter()
-        self.mp3WithID3TagBuilder = Mp3WithID3TagBuilder(id3TagCreator: ID3TagCreatorFactory.make(),
+        self.mp3WithID3TagBuilder = Mp3WithID3TagBuilder(id3TagCreator: id3TagCreator,
                                                          id3TagConfiguration: ID3TagConfiguration())
     }
 
@@ -68,8 +70,8 @@ public class ID3TagEditor {
      ID3 tag).
      */
     public func write(tag: ID3Tag, to path: String, andSaveTo newPath: String? = nil) throws {
-        let newId3TagData = try mp3WithID3TagBuilder.build(mp3: Data(), newId3Tag: tag, currentId3Tag: nil)
         let currentId3Tag = try read(from: path)
+        let newId3TagData = try id3TagCreator.create(id3Tag: tag)
         try mp3FileWriter.write(newId3TagData: newId3TagData, currentId3Tag: currentId3Tag, fromPath: path, toPath: newPath ?? path)
     }
 

Source/Mp3/Mp3FileReader.swift

@@ -57,6 +57,7 @@ class Mp3FileReader {
         }
 
         inputStream.open()
+        defer { inputStream.close() }
 
         let headerSize = id3TagConfiguration.headerSize()
         let header = try read(bytesCount: headerSize, fromStream: inputStream)

Tests/Mp3/Mp3FileWriterTest.swift

@@ -0,0 +1,37 @@
+//
+//  Mp3FileWriterTest.swift
+//  ID3TagEditor
+//
+//  Created by Fabian Zwick on 18.10.24.
+//
+
+import Foundation
+import Testing
+
+@testable import ID3TagEditor
+
+struct Mp3FileWriterTest {
+    @Test func testWritingWithCurrentTag() throws {
+        let newTag = ID32v3TagBuilder()
+            .title(frame: .init(content: "Test Title"))
+            .album(frame: .init(content: "Test Album"))
+            .build()
+
+        let id3TagCreator = ID3TagCreatorFactory.make()
+        let newId3TagData = try id3TagCreator.create(id3Tag: newTag)
+
+        let fromPath = PathLoader().pathFor(name: "example", fileType: "mp3")
+        let currentId3Tag = try ID3TagEditor().read(from: fromPath)
+
+        let pathMp3Generated =  NSHomeDirectory() + "/testWritingWithCurrentTagAndEqualToPath.mp3"
+        #expect(throws: Never.self) { try Mp3FileWriter().write(newId3TagData: newId3TagData, currentId3Tag: currentId3Tag, fromPath: fromPath, toPath: pathMp3Generated) }
+
+        let readTag = try ID3TagEditor().read(from: pathMp3Generated)
+        #expect((readTag?.frames[.title] as? ID3FrameWithStringContent)?.content == "Test Title")
+        #expect((readTag?.frames[.album] as? ID3FrameWithStringContent)?.content == "Test Album")
+    }
+
+    static let allTests = [
+        ("testWritingWithCurrentTag", testWritingWithCurrentTag)
+    ]
+}

Tests/Parse/ID3TagSizeParserTest.swift

@@ -21,8 +21,14 @@ struct ID3TagSizeParserTest {
         #expect(ID3TagSizeParser().parse(data: mp3V23) == 245864)
     }
 
+    @Test func parseTagSizeToBeModified() {
+        let mp3 = NSData(contentsOfFile: PathLoader().pathFor(name: "example-to-be-modified", fileType: "mp3"))!
+        #expect(ID3TagSizeParser().parse(data: mp3) < mp3.count)
+    }
+
     static let allTests = [
         ("parseTagSizeV2", parseTagSizeV2),
-        ("parseFrameContentSizeV3", parseTagSizeV3)
+        ("parseFrameContentSizeV3", parseTagSizeV3),
+        ("parseTagSizeToBeModified", parseTagSizeToBeModified)
     ]
 }