Extract preview line with preview data (#194)

Sources/SnapshotPreviewsCore/SnapshotPreviewsCore.swift

@@ -88,6 +88,7 @@ public struct PreviewType: Hashable, Identifiable {
  init<A: PreviewProvider>(typeName: String, previewProvider: A.Type) {
  self.typeName = typeName
  self.fileID = nil
+ self.line = nil
  self.previews = A._allPreviews.map { Preview(preview: $0, type: A.self) }
  self.platform = A.platform
  }
@@ -98,6 +99,7 @@ public struct PreviewType: Hashable, Identifiable {
  init?<A: PreviewRegistry>(typeName: String, registry: A.Type) {
  self.typeName = typeName
  self.fileID = A.fileID
+ self.line = A.line
  guard let internalPreview = try? A.makePreview(), let preview = Preview(preview: internalPreview) else {
  return nil
  }
@@ -120,7 +122,11 @@ public struct PreviewType: Hashable, Identifiable {
 
  public var displayName: String {
  if let fileID = fileID {
- return String(fileID.split(separator: "/").last!.split(separator: ".").first!)
+ let basename = String(fileID.split(separator: "/").last!.split(separator: ".").first!)
+ if let line = line {
+ return "\(basename)#\(line)"
+ }
+ return basename
  }
  let components = typeName
  .split(separator: ".")
@@ -138,6 +144,7 @@ public struct PreviewType: Hashable, Identifiable {
 
  public let id = UUID()
  public let fileID: String?
+ public let line: Int?
  public let typeName: String
  public var previews: [Preview]
  public let platform: PreviewPlatform?