[gtkmm] Gdk::RGBA: Add fairly simple test of our additions

[Daniel Boles <dboles src gnome org>]

commit 37d4ab71eebece0fc1be46dd3538d3446cedb8a6
Author: Daniel Boles <dboles src gnome org>
Date:   Mon Dec 17 21:12:09 2018 +0000

    Gdk::RGBA: Add fairly simple test of our additions
    
    Test the new constructor from #40, the fix for #42, and some other bits
    that we add. Most other tests should be added to GTK itself, not gtkmm.
    
    https://gitlab.gnome.org/GNOME/gtkmm/merge_requests/8#note_389465

 tests/Makefile.am      |  3 +++
 tests/gdk_rgba/main.cc | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index fce2d663..01e3466c 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -24,6 +24,7 @@ check_PROGRAMS =                      \
        child_widget_managed/test       \
        delete_cpp_child/test           \
        dialog_deletethis/test          \
+       gdk_rgba/test \
        main_with_options/test          \
        menu_destruction/test           \
        object_move/test                \
@@ -34,6 +35,7 @@ check_PROGRAMS =                      \
        wrap_existing/test
 
 TESTS =        object_move/test \
+  gdk_rgba/test \
   test_validate_docs_xhtml.sh
 
 builder_test_SOURCES               = builder/main.cc
@@ -44,6 +46,7 @@ child_widget2_test_SOURCES         = child_widget2/main.cc
 child_widget_managed_test_SOURCES  = child_widget_managed/main.cc
 delete_cpp_child_test_SOURCES      = delete_cpp_child/main.cc
 dialog_deletethis_test_SOURCES     = dialog_deletethis/main.cc
+gdk_rgba_test_SOURCES              = gdk_rgba/main.cc
 main_with_options_test_SOURCES     = main_with_options/main.cc
 menu_destruction_test_SOURCES      = menu_destruction/main.cc
 object_move_test_SOURCES           = object_move/main.cc
diff --git a/tests/gdk_rgba/main.cc b/tests/gdk_rgba/main.cc
new file mode 100644
index 00000000..d692cffd
--- /dev/null
+++ b/tests/gdk_rgba/main.cc
@@ -0,0 +1,55 @@
+#include <gdkmm/rgba.h>
+#include <glib.h>
+
+int
+main()
+{
+  // A default-constructed RGBA is black and fully transparent
+  auto rgba = Gdk::RGBA{};
+  g_assert_cmpfloat(rgba.get_red  (), ==, 0.0);
+  g_assert_cmpfloat(rgba.get_green(), ==, 0.0);
+  g_assert_cmpfloat(rgba.get_blue (), ==, 0.0);
+  g_assert_cmpfloat(rgba.get_alpha(), ==, 0.0);
+
+  // Test that when passing r,g,b the alpha defaults to 1
+  rgba.set_rgba(0.0, 0.0, 0.0);
+  g_assert_cmpfloat(rgba.get_alpha(), ==, 1.0);
+
+  // Test our get_*_u(). Note only the min/max `u`s are reliable due to rounding
+  g_assert_cmpint(rgba.get_red_u  (), ==, 0x0000);
+  g_assert_cmpint(rgba.get_green_u(), ==, 0x0000);
+  g_assert_cmpint(rgba.get_blue_u (), ==, 0x0000);
+  g_assert_cmpint(rgba.get_alpha_u(), ==, 0xFFFF);
+
+  // Test constructor from doubles added in GitLab Issue #40
+  auto rgba2 = Gdk::RGBA{0.0, 0.0, 0.0, 1.0};
+  g_assert_true(rgba == rgba2);
+
+  // Test our set_*_u()
+  rgba.set_rgba(1.0, 1.0, 1.0, 1.0);
+  rgba2.set_rgba_u(0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF);
+  g_assert_true(rgba == rgba2);
+
+  // and set_grey*()
+  rgba2.set_grey(1.0, 1.0);
+  g_assert_true(rgba == rgba2);
+  rgba2.set_grey_u(0xFFFF, 0xFFFF);
+  g_assert_true(rgba == rgba2);
+
+  // Test that hues 0° and 360° both result in red, fixed in GitLab Issue #42
+  rgba.set_hsv(0.0, 1.0, 1.0);
+  g_assert_cmpfloat(rgba.get_red  (), ==, 1.0);
+  g_assert_cmpfloat(rgba.get_green(), ==, 0.0);
+  g_assert_cmpfloat(rgba.get_blue (), ==, 0.0);
+  g_assert_cmpfloat(rgba.get_alpha(), ==, 1.0);
+  rgba2.set_hsv(360.0, 1.0, 1.0);
+  g_assert_true(rgba == rgba2);
+
+  // Test HSL the same way
+  rgba2.set_hsl(0.0, 1.0, 0.5);
+  g_assert_true(rgba == rgba2);
+  rgba2.set_hsl(360.0, 1.0, 0.5);
+  g_assert_true(rgba == rgba2);
+
+  return 0;
+}