Add unit test for wxFlexGridSizer layout logic.

Currently just test that wxEXPAND flag works as expected.

tests/sizers/gridsizer.cpp

@@ -0,0 +1,139 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        tests/sizers/gridsizer.cpp
+// Purpose:     Unit tests for wxGridSizer and wxFlexGridSizer.
+// Author:      Vadim Zeitlin
+// Created:     2015-04-03
+// Copyright:   (c) 2015 Vadim Zeitlin <vadim@wxwidgets.org>
+///////////////////////////////////////////////////////////////////////////////
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+#include "testprec.h"
+
+#ifdef __BORLANDC__
+    #pragma hdrstop
+#endif
+
+#ifndef WX_PRECOMP
+    #include "wx/app.h"
+    #include "wx/sizer.h"
+    #include "wx/vector.h"
+#endif // WX_PRECOMP
+
+#include "asserthelper.h"
+
+// ----------------------------------------------------------------------------
+// test class
+// ----------------------------------------------------------------------------
+
+class GridSizerTestCase : public CppUnit::TestCase
+{
+public:
+    GridSizerTestCase() { }
+
+    virtual void setUp();
+    virtual void tearDown();
+
+private:
+    CPPUNIT_TEST_SUITE( GridSizerTestCase );
+        CPPUNIT_TEST( Expand );
+    CPPUNIT_TEST_SUITE_END();
+
+    void Expand();
+
+    // Clear the current sizer contents and add the specified windows to it,
+    // using the same flags for all of them.
+    void SetChildren(const wxVector<wxWindow*>& children,
+                     const wxSizerFlags& flags);
+
+    wxWindow *m_win;
+    wxFlexGridSizer *m_sizer;
+
+    DECLARE_NO_COPY_CLASS(GridSizerTestCase)
+};
+
+// register in the unnamed registry so that these tests are run by default
+CPPUNIT_TEST_SUITE_REGISTRATION( GridSizerTestCase );
+
+// also include in its own registry so that these tests can be run alone
+CPPUNIT_TEST_SUITE_NAMED_REGISTRATION( GridSizerTestCase, "GridSizerTestCase" );
+
+// ----------------------------------------------------------------------------
+// test initialization
+// ----------------------------------------------------------------------------
+
+void GridSizerTestCase::setUp()
+{
+    m_win = new wxWindow(wxTheApp->GetTopWindow(), wxID_ANY);
+    m_win->SetClientSize(127, 35);
+
+    m_sizer = new wxFlexGridSizer(2);
+    m_win->SetSizer(m_sizer);
+}
+
+void GridSizerTestCase::tearDown()
+{
+    delete m_win;
+    m_win = NULL;
+
+    m_sizer = NULL;
+}
+
+// ----------------------------------------------------------------------------
+// helpers
+// ----------------------------------------------------------------------------
+
+void GridSizerTestCase::SetChildren(const wxVector<wxWindow*>& children,
+                                    const wxSizerFlags& flags)
+{
+    m_sizer->Clear();
+    for ( wxVector<wxWindow*>::const_iterator i = children.begin();
+          i != children.end();
+          ++i )
+    {
+        m_sizer->Add(*i, flags);
+    }
+
+    m_win->Layout();
+}
+
+// ----------------------------------------------------------------------------
+// tests themselves
+// ----------------------------------------------------------------------------
+
+void GridSizerTestCase::Expand()
+{
+    const wxSize sizeTotal = m_win->GetClientSize();
+    const wxSize sizeChild(sizeTotal.x / 4, sizeTotal.y / 4);
+    const wxSize sizeRest(sizeTotal.x - sizeTotal.x / 4,
+                          sizeTotal.y - sizeTotal.y / 4);
+
+    wxVector<wxWindow*> children;
+    for ( int n = 0; n < 4; n++ )
+    {
+        children.push_back(new wxWindow(m_win, wxID_ANY, wxDefaultPosition,
+                                        sizeChild));
+    }
+
+    m_sizer->AddGrowableRow(1);
+    m_sizer->AddGrowableCol(1);
+
+    // Without Expand() windows have their initial size.
+    SetChildren(children, wxSizerFlags());
+    CPPUNIT_ASSERT_EQUAL( sizeChild, children[0]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( sizeChild, children[1]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( sizeChild, children[2]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( sizeChild, children[3]->GetSize() );
+
+    // With just expand, they expand to fill the entire column and the row
+    // containing them (which may or not expand on its own).
+    SetChildren(children, wxSizerFlags().Expand());
+    CPPUNIT_ASSERT_EQUAL( sizeChild, children[0]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( wxSize(sizeRest.x, sizeChild.y),
+                          children[1]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( wxSize(sizeChild.x, sizeRest.y),
+                          children[2]->GetSize() );
+    CPPUNIT_ASSERT_EQUAL( sizeRest, children[3]->GetSize() );
+}