RecordingWindowBackend

RecordingWindowBackend is a mock implementation of IHermesWindowBackend that records all interactions for verification in tests. It also supports simulating events to test application responses.

Overview

The recording backend captures:

• Method calls with arguments and timestamps
• Property changes with old/new values
• Events raised
• Web messages sent and received
• Navigation history
• Custom titlebar drag actions
• Custom scheme registrations

Properties

State Properties

Property	Type	Description
IsInitialized	bool	Whether Initialize() was called
IsShown	bool	Whether Show() was called
IsClosed	bool	Whether Close() was called
InitialOptions	HermesWindowOptions?	Options passed to Initialize()

Window State

Property	Type	Description
Title	string	Current window title
Size	(int Width, int Height)	Current window size
Position	(int X, int Y)	Current window position
IsMaximized	bool	Whether window is maximized
IsMinimized	bool	Whether window is minimized

Platform Simulation

var backend = new RecordingWindowBackend();
backend.Platform = HermesPlatform.macOS; // Simulate macOS

// Now your code can check backend.Platform and behave accordingly

Recording Access

Access recorded data through the Recording property:

var recording = backend.Recording;

// Check method calls
recording.MethodWasCalled("Show");

// Check navigation
recording.NavigatedTo("https://example.com");
recording.NavigatedToPattern("example");

// Check web messages
recording.SentWebMessageMatching("response");
recording.ReceivedWebMessageMatching("request");

// Check events
recording.EventWasRaised("Maximized");

WindowBackendRecording Collections

Property	Type	Description
MethodCalls	IReadOnlyList<MethodCall>	All method invocations
PropertyChanges	IReadOnlyList<PropertyChange>	All property mutations
Events	IReadOnlyList<RecordedEvent>	All events raised
WebMessagesReceived	IReadOnlyList<string>	Messages from JavaScript
WebMessagesSent	IReadOnlyList<string>	Messages to JavaScript
Navigations	IReadOnlyList<string>	URLs navigated to
LastDragAction	string?	Last drag region action

Record Types

// Method call record
public record MethodCall
{
    public string MethodName { get; init; }
    public object?[] Arguments { get; init; }
    public DateTimeOffset Timestamp { get; init; }
}

// Property change record
public record PropertyChange
{
    public string PropertyName { get; init; }
    public object? OldValue { get; init; }
    public object? NewValue { get; init; }
    public DateTimeOffset Timestamp { get; init; }
}

// Event record
public record RecordedEvent
{
    public string EventName { get; init; }
    public object?[] Arguments { get; init; }
    public DateTimeOffset Timestamp { get; init; }
}

Event Simulation

Window Events

backend.SimulateResize(1920, 1080);   // Fires Resized event
backend.SimulateMove(100, 200);       // Fires Moved event
backend.SimulateMaximize();           // Fires Maximized event
backend.SimulateRestore();            // Fires Restored event
backend.SimulateFocusIn();            // Fires FocusIn event
backend.SimulateFocusOut();           // Fires FocusOut event

Web Messages

// Simulate JavaScript sending a message to C#
backend.SimulateWebMessage("""{"type":"click","id":42}""");

Custom Titlebar Drag Regions

backend.SimulateDragRegionClick();       // User clicked on drag region
backend.SimulateDragRegionDoubleClick(); // User double-clicked (maximize)
backend.SimulateNonDragRegionClick();    // User clicked non-drag area

Custom Scheme Testing

Test custom resource schemes:

// Register a scheme handler
backend.RegisterCustomScheme("app", url =>
{
    if (url.EndsWith("style.css"))
    {
        var stream = new MemoryStream(Encoding.UTF8.GetBytes("body { }"));
        return (stream, "text/css");
    }
    return (null, null);
});

// Verify registration
Assert.True(backend.HasCustomScheme("app"));

// Test the handler
var (content, contentType) = backend.TestCustomScheme("app", "app://style.css")!.Value;
Assert.Equal("text/css", contentType);

Threading Simulation

The backend supports testing async operations:

// Queue an action (doesn't execute immediately when off UI thread)
backend.BeginInvoke(() => DoSomething());

// Process queued actions (simulates UI thread processing)
backend.ProcessPending();

Clearing Recordings

Reset recorded data between test phases:

backend.Recording.Clear();

Example: Verifying Method Call Sequence

[Fact]
public void Window_InitializesInCorrectOrder()
{
    var backend = new RecordingWindowBackend();
    var window = new HermesWindow(backend);

    window.SetTitle("Test").SetSize(800, 600);
    window.Show();

    var methods = backend.Recording.MethodCalls.Select(c => c.MethodName).ToList();

    Assert.Equal("Initialize", methods[0]);
    Assert.Equal("Show", methods[1]);
}

See Also

• TestableHermesWindow — High-level test wrapper
• HermesAssert — Fluent assertions
• Testing Examples — Common patterns