Add unit test: image.load_basic()

[MyreMylar]

This function needs a unit test.

Guide to how to contribute to an open source project on GitHub.
Draft guide on how to write a unit test for pygame

Test stub: https://github.com/pygame/pygame/blob/master/test/image_test.py#L541-L549
Docs: None.
Code to be tested: https://github.com/pygame/pygame/blob/master/src_c/image.c#L67-L112

[williams-c]

I'll work on this one if that's alright

[dtomci]

Hello, can I try to do this ?

[MyreMylar]

Sure, it's been a few months. There is some discussion of the function in another issue recently that might be of interest:

#1732

[bwright8]

May I work on this and ask a couple questions? It is ok to recycle code from other tests? How many filetypes should be tested?

[MyreMylar]

I believe load_basic() only loads .bmp files, however there are a couple of loading paths (loading from a file on disc directly, loading from bmp data in a file .like object in memory). Recycling code from other tests is OK, in fact there has been one nearly done attempt at this test already in a PR that you should look at here:

#2225

So you know where we got to and what was missing from that go around.

Worth looking at the underlying C code as well:

pygame/src_c/image.c

Lines 83 to 128 in 4306f7a

	static PyObject *
	image_load_basic(PyObject *self, PyObject *arg)
	{
	PyObject *obj;
	PyObject *final;
	PyObject *oencoded;
	const char *name = NULL;
	SDL_Surface *surf;
	if (!PyArg_ParseTuple(arg, "O|s", &obj, &name)) {
	return NULL;
	}
	oencoded = pg_EncodeString(obj, "UTF-8", NULL, pgExc_SDLError);
	if (oencoded == NULL) {
	return NULL;
	}
	if (oencoded != Py_None) {
	Py_BEGIN_ALLOW_THREADS;
	surf = SDL_LoadBMP(Bytes_AS_STRING(oencoded));
	Py_END_ALLOW_THREADS;
	Py_DECREF(oencoded);
	}
	else {
	SDL_RWops *rw;
	Py_DECREF(oencoded);
	rw = pgRWops_FromFileObject(obj);
	if (rw == NULL) {
	return NULL;
	}
	Py_BEGIN_ALLOW_THREADS;
	surf = SDL_LoadBMP_RW(rw, 1);
	Py_END_ALLOW_THREADS;
	}
	if (surf == NULL) {
	return RAISE(pgExc_SDLError, SDL_GetError());
	}
	final = (PyObject *)pgSurface_New(surf);
	if (final == NULL) {
	SDL_FreeSurface(surf);
	}
	return final;
	}