Add a simple wxBitmapBundle unit test

Check for the minimal functionality when using vector-based
implementation.

tests/graphics/bmpbundle.cpp

@@ -0,0 +1,48 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        tests/graphics/bmpbundle.cpp
+// Purpose:     wxBitmapBundle unit test
+// Author:      Vadim Zeitlin
+// Created:     2021-09-27
+// Copyright:   (c) 2021 Vadim Zeitlin <vadim@wxwidgets.org>
+///////////////////////////////////////////////////////////////////////////////
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+#include "testprec.h"
+
+#include "wx/bmpbndl.h"
+
+#include "asserthelper.h"
+
+// ----------------------------------------------------------------------------
+// tests
+// ----------------------------------------------------------------------------
+
+TEST_CASE("BitmapBundle::Create", "[bmpbundle]")
+{
+    wxBitmapBundle b;
+    CHECK( !b.IsOk() );
+    CHECK( b.GetDefaultSize() == wxDefaultSize );
+
+    b = wxBitmap(16, 16);
+    CHECK( b.IsOk() );
+    CHECK( b.GetDefaultSize() == wxSize(16, 16) );
+}
+
+TEST_CASE("BitmapBundle::FromBitmaps", "[bmpbundle]")
+{
+    wxVector<wxBitmap> bitmaps;
+    bitmaps.push_back(wxBitmap(16, 16));
+    bitmaps.push_back(wxBitmap(24, 24));
+
+    wxBitmapBundle b = wxBitmapBundle::FromBitmaps(bitmaps);
+    REQUIRE( b.IsOk() );
+    CHECK( b.GetDefaultSize() == wxSize(16, 16) );
+
+    CHECK( b.GetBitmap(wxDefaultSize ).GetSize() == wxSize(16, 16) );
+    CHECK( b.GetBitmap(wxSize(16, 16)).GetSize() == wxSize(16, 16) );
+    CHECK( b.GetBitmap(wxSize(20, 20)).GetSize() == wxSize(20, 20) );
+    CHECK( b.GetBitmap(wxSize(24, 24)).GetSize() == wxSize(24, 24) );
+}