Add some joystick flag tests.

The important checks are the ones done with the invertX&Y apply. The isJoystickFlagged checks are sanity checks, you could replace those with whatever you use for flag testing next @csmartdalton.

Note that the flag value is loaded via core (auto-generated) as a raw uint32_t:
https://github.com/rive-app/rive/blob/eef7de3b1a5b34a3deb3591781ab9ca2d6e15f0d/packages/runtime/include/rive/generated/joystick_base.hpp#L170

Diffs=
7bbf083ce Add some joystick flag tests. (#5921)

Co-authored-by: Luigi Rosso <luigi-rosso@users.noreply.github.com>

.rive_head

@@ -1 +1 @@
-d35df04272e659d8244c776e9c4f558452888501
+7bbf083ce32d92ba240dbf08b852d2702fac18ca

test/joystick_flags_test.cpp

@@ -0,0 +1,54 @@
+#include "rive/joystick.hpp"
+#include "rive/shapes/shape.hpp"
+#include "rive_file_reader.hpp"
+#include "rive_testing.hpp"
+
+TEST_CASE("joystick flags load as expected", "[file]")
+{
+    auto file = ReadRiveFile("../../test/assets/joystick_flag_test.riv");
+    auto artboard = file->artboard();
+
+    auto invertX = artboard->find<rive::Joystick>("Invert X Joystick");
+    REQUIRE(invertX->isJoystickFlagged(rive::JoystickFlags::invertX));
+    REQUIRE(!invertX->isJoystickFlagged(rive::JoystickFlags::invertY));
+    REQUIRE(!invertX->isJoystickFlagged(rive::JoystickFlags::worldSpace));
+
+    invertX->x(0.0f);
+    invertX->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_x_rect")->x() == 350.0f);
+
+    invertX->x(1.0f);
+    invertX->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_x_rect")->x() == 300.0f);
+
+    invertX->x(-1.0f);
+    invertX->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_x_rect")->x() == 400.0f);
+
+    auto invertY = artboard->find<rive::Joystick>("Invert Y Joystick");
+    REQUIRE(!invertY->isJoystickFlagged(rive::JoystickFlags::invertX));
+    REQUIRE(invertY->isJoystickFlagged(rive::JoystickFlags::invertY));
+    REQUIRE(!invertY->isJoystickFlagged(rive::JoystickFlags::worldSpace));
+
+    invertY->y(0.0f);
+    invertY->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_y_ellipse")->x() == 425.0f);
+
+    invertY->y(1.0f);
+    invertY->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_y_ellipse")->x() == 400.0f);
+
+    invertY->y(-1.0f);
+    invertY->apply(artboard);
+    REQUIRE(artboard->find<rive::Shape>("invert_y_ellipse")->x() == 450.0f);
+
+    auto world = artboard->find<rive::Joystick>("World Joystick");
+    REQUIRE(!world->isJoystickFlagged(rive::JoystickFlags::invertX));
+    REQUIRE(!world->isJoystickFlagged(rive::JoystickFlags::invertY));
+    REQUIRE(world->isJoystickFlagged(rive::JoystickFlags::worldSpace));
+
+    auto normal = artboard->find<rive::Joystick>("Normal Joystick");
+    REQUIRE(!normal->isJoystickFlagged(rive::JoystickFlags::invertX));
+    REQUIRE(!normal->isJoystickFlagged(rive::JoystickFlags::invertY));
+    REQUIRE(!normal->isJoystickFlagged(rive::JoystickFlags::worldSpace));
+}