Add experimental AdvancedConsoleOutputRecorder skeleton framework

Sources/Testing/ABI/EntryPoints/EntryPoint.swift

@@ -54,12 +54,29 @@ func entryPoint(passing args: __CommandLineArguments_v0?, eventHandler: Event.Ha
 #if !SWT_NO_FILE_IO
     // Configure the event recorder to write events to stderr.
     if configuration.verbosity > .min {
-      let eventRecorder = Event.ConsoleOutputRecorder(options: .for(.stderr)) { string in
-        try? FileHandle.stderr.write(string)
-      }
-      configuration.eventHandler = { [oldEventHandler = configuration.eventHandler] event, context in
-        eventRecorder.record(event, in: context)
-        oldEventHandler(event, context)
+      // Check for experimental console output flag
+      if Environment.flag(named: "SWT_ENABLE_EXPERIMENTAL_CONSOLE_OUTPUT") == true {
+        // Use experimental AdvancedConsoleOutputRecorder
+        var advancedOptions = Event.AdvancedConsoleOutputRecorder.Options()
+        advancedOptions.base = .for(.stderr)
+
+        let eventRecorder = Event.AdvancedConsoleOutputRecorder(options: advancedOptions) { string in
+          try? FileHandle.stderr.write(string)
+        }
+
+        configuration.eventHandler = { [oldEventHandler = configuration.eventHandler] event, context in
+          eventRecorder.handle(event, in: context)
+          oldEventHandler(event, context)
+        }
+      } else {
+        // Use the standard console output recorder (default behavior)
+        let eventRecorder = Event.ConsoleOutputRecorder(options: .for(.stderr)) { string in
+          try? FileHandle.stderr.write(string)
+        }
+        configuration.eventHandler = { [oldEventHandler = configuration.eventHandler] event, context in
+          eventRecorder.record(event, in: context)
+          oldEventHandler(event, context)
+        }
       }
     }
 #endif

Sources/Testing/CMakeLists.txt

@@ -27,6 +27,7 @@ add_library(Testing
   Attachments/Attachment.swift
   Events/Clock.swift
   Events/Event.swift
+  Events/Recorder/Event.AdvancedConsoleOutputRecorder.swift
   Events/Recorder/Event.ConsoleOutputRecorder.swift
   Events/Recorder/Event.HumanReadableOutputRecorder.swift
   Events/Recorder/Event.JUnitXMLRecorder.swift
@@ -82,6 +83,7 @@ add_library(Testing
   Support/GetSymbol.swift
   Support/Graph.swift
   Support/JSON.swift
+  Support/LiveUpdatingLine.swift
   Support/Locked.swift
   Support/Locked+Platform.swift
   Support/Versions.swift

Sources/Testing/Events/Recorder/Event.AdvancedConsoleOutputRecorder.swift

@@ -0,0 +1,79 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+extension Event {
+  /// An experimental console output recorder that provides enhanced test result
+  /// display capabilities.
+  ///
+  /// This recorder is currently experimental and must be enabled via the
+  /// `SWT_ENABLE_EXPERIMENTAL_CONSOLE_OUTPUT` environment variable.
+  ///
+  /// Future capabilities will include:
+  /// - Hierarchical test result display with tree visualization
+  /// - Live progress indicators during test execution
+  /// - Enhanced SF Symbols integration on supported platforms
+  struct AdvancedConsoleOutputRecorder: Sendable {
+    /// Configuration options for the advanced console output recorder.
+    struct Options: Sendable {
+      /// Base console output recorder options to inherit from.
+      var base: Event.ConsoleOutputRecorder.Options
+
+      /// Whether to enable experimental hierarchical output display.
+      /// Currently unused - reserved for future PR #2.
+      var useHierarchicalOutput: Bool
+
+      /// Whether to show successful tests in the output.
+      /// Currently unused - reserved for future PR #2.
+      var showSuccessfulTests: Bool
+
+      init() {
+        self.base = Event.ConsoleOutputRecorder.Options()
+        self.useHierarchicalOutput = true
+        self.showSuccessfulTests = true
+      }
+    }
+
+    /// The options for this recorder.
+    let options: Options
+
+    /// The write function for this recorder.
+    let write: @Sendable (String) -> Void
+
+    /// The fallback console recorder for standard output.
+    private let _fallbackRecorder: Event.ConsoleOutputRecorder
+
+    /// Initialize the advanced console output recorder.
+    ///
+    /// - Parameters:
+    ///   - options: Configuration options for the recorder.
+    ///   - write: A closure that writes output to its destination.
+    init(options: Options = Options(), writingUsing write: @escaping @Sendable (String) -> Void) {
+      self.options = options
+      self.write = write
+      self._fallbackRecorder = Event.ConsoleOutputRecorder(options: options.base, writingUsing: write)
+    }
+  }
+}
+
+extension Event.AdvancedConsoleOutputRecorder {
+  /// Handle an event by processing it and generating appropriate output.
+  ///
+  /// Currently this is a skeleton implementation that delegates to the
+  /// standard ConsoleOutputRecorder.
+  ///
+  /// - Parameters:
+  ///   - event: The event to handle.
+  ///   - eventContext: The context associated with the event.
+  func handle(_ event: borrowing Event, in eventContext: borrowing Event.Context) {
+    // Skeleton implementation: delegate to standard recorder
+    // Future PRs will add enhanced functionality here
+    _fallbackRecorder.record(event, in: eventContext)
+  }
+}

Sources/Testing/Support/LiveUpdatingLine.swift

@@ -0,0 +1,31 @@
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
+//
+
+/// Prints a string to the console by overwriting the current line without creating a new line.
+/// This is ideal for creating single-line, live-updating progress bars or status indicators.
+///
+/// - Parameter text: The text to display on the current line
+///
+/// ## Technical Details
+/// - Uses carriage return (`\r`) to move cursor to beginning of current line
+/// - Uses ANSI escape code (`\u{001B}[2K`) to clear the entire line
+/// - Does not append a newline character, allowing the line to be overwritten again
+///
+/// ## Example Usage
+/// ```swift
+/// printLiveUpdatingLine("Processing... 25%")
+/// // Later...
+/// printLiveUpdatingLine("Processing... 50%")
+/// // Later...
+/// printLiveUpdatingLine("Processing... 100%")
+/// ```
+public func printLiveUpdatingLine(_ text: String) {
+  print("\r\u{001B}[2K\(text)", terminator: "")
+}