Add singleton support & tests

Author: touilleMan

src/godot/classes.pxd.j2

@@ -99,6 +99,6 @@ cdef class {{ cls.cy_type }}({{ cls.inherits.cy_type if cls.inherits else "" }})
 
 
 cdef object _load_class(str name)
-cdef object _load_singleton(str name)
+cpdef object _load_singleton(str name)
 cdef void _cleanup_loaded_classes_and_singletons()
 cdef object _object_call(gd_object_t obj, str meth, list args)

src/godot/classes.pyx.j2

@@ -102,7 +102,7 @@ cdef void _cleanup_loaded_classes_and_singletons():
     _loaded_classes.clear()
 
 
-cdef object _load_singleton(str name):
+cpdef object _load_singleton(str name):
     try:
         return _loaded_singletons[name]
     except KeyError:
@@ -113,6 +113,10 @@ cdef object _load_singleton(str name):
     cdef gd_string_name_t gdname = gdapi.gd_string_name_from_unchecked_pystr(name)
     cdef gd_object_t gdobj = gdptrs.gdptr_global_get_singleton(&gdname)
     gdapi.gd_string_name_del(&gdname)
+
+    if gdobj == NULL:
+        raise RuntimeError(f"Singleton `{name}` doesn't exist in Godot !")
+
     cdef object singleton = cls._from_ptr(<size_t>gdobj)
 
     _loaded_singletons[name] = singleton

src/godot/meson.build

@@ -11,7 +11,7 @@ subdir('hazmat')
 ##############################################################################
 
 
-foreach src: ['__init__.py', '__init__.pyi', 'py.typed']
+foreach src: ['__init__.py', 'singletons.py', '__init__.pyi', 'py.typed']
     install_data(
         src,
         install_dir: join_paths(python_site_packages_install_path, 'godot'),

src/godot/singletons.py

@@ -0,0 +1,8 @@
+from .classes import _load_singleton
+
+
+def __getattr__(name: str):
+    try:
+        return _load_singleton(name)
+    except RuntimeError:
+        raise AttributeError

tests/4-use-godot-from-python/tests/test_singletons.py

@@ -1 +1,11 @@
-# TODO
+from clodotest import assert_isinstance
+import godot
+
+
+def test_access():
+    from godot.classes import OS as _OS
+    from godot.singletons import OS
+
+    assert_isinstance(OS, _OS)
+    assert_isinstance(OS.delta_smoothing, bool)
+    assert_isinstance(OS.get_config_dir(), godot.GDString)