tests: add buffer transform tests

This patch continues the buffer and output transforms testing by iterating
through a representative selection of buffer transforms and scales.

For more details, see the previous patch "tests: add output transform tests".

https://gitlab.freedesktop.org/wayland/weston/issues/52

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
diff --git a/tests/buffer-transforms-test.c b/tests/buffer-transforms-test.c
new file mode 100644
index 0000000..fdc86bb
--- /dev/null
+++ b/tests/buffer-transforms-test.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright © 2020 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/mman.h>
+
+#include "weston-test-client-helper.h"
+#include "weston-test-fixture-compositor.h"
+
+#define TRANSFORM(x) WL_OUTPUT_TRANSFORM_ ## x, #x
+#define RENDERERS(s, t) \
+	{ RENDERER_PIXMAN, s, TRANSFORM(t) }, \
+	{ RENDERER_GL,     s, TRANSFORM(t) }
+
+struct setup_args {
+	enum renderer_type renderer;
+	int scale;
+	enum wl_output_transform transform;
+	const char *transform_name;
+};
+
+static const struct setup_args my_setup_args[] = {
+	RENDERERS(1, NORMAL),
+	RENDERERS(2, 90),
+};
+
+static enum test_result_code
+fixture_setup(struct weston_test_harness *harness, const struct setup_args *arg)
+{
+	struct compositor_setup setup;
+
+	/* The width and height are chosen to produce 324x240 framebuffer, to
+	 * emulate keeping the video mode constant.
+	 * This resolution is divisible by 2 and 3.
+	 * Headless multiplies the given size by scale.
+	 */
+
+	compositor_setup_defaults(&setup);
+	setup.renderer = arg->renderer;
+	setup.width = 324 / arg->scale;
+	setup.height = 240 / arg->scale;
+	setup.scale = arg->scale;
+	setup.transform = arg->transform;
+	setup.shell = SHELL_TEST_DESKTOP;
+
+	return weston_test_harness_execute_as_client(harness, &setup);
+}
+DECLARE_FIXTURE_SETUP_WITH_ARG(fixture_setup, my_setup_args);
+
+struct buffer_args {
+	int scale;
+	enum wl_output_transform transform;
+	const char *transform_name;
+};
+
+static const struct buffer_args my_buffer_args[] = {
+	/* { 1, TRANSFORM(NORMAL) }, done in output-transforms-test.c */
+	{ 1, TRANSFORM(90) },
+	{ 1, TRANSFORM(180) },
+	{ 1, TRANSFORM(270) },
+	{ 1, TRANSFORM(FLIPPED) },
+	{ 1, TRANSFORM(FLIPPED_90) },
+	{ 1, TRANSFORM(FLIPPED_180) },
+	{ 1, TRANSFORM(FLIPPED_270) },
+	{ 2, TRANSFORM(NORMAL) },
+	/* { 2, TRANSFORM(90) }, done in output-transforms-test.c */
+	{ 2, TRANSFORM(180) },
+	{ 2, TRANSFORM(FLIPPED) },
+	{ 3, TRANSFORM(NORMAL) },
+	{ 3, TRANSFORM(FLIPPED_90) },
+};
+
+TEST_P(buffer_transform, my_buffer_args)
+{
+	const struct buffer_args *bargs = data;
+	const struct setup_args *oargs;
+	struct client *client;
+	bool match;
+	char *refname;
+	int ret;
+
+	oargs = &my_setup_args[get_test_fixture_index()];
+
+	ret = asprintf(&refname, "output_%d-%s_buffer_%d-%s",
+		       oargs->scale, oargs->transform_name,
+		       bargs->scale, bargs->transform_name);
+	assert(ret);
+
+	testlog("%s: %s\n", get_test_name(), refname);
+
+	/*
+	 * NOTE! The transform set below is a lie.
+	 * Take that into account when analyzing screenshots.
+	 */
+
+	client = create_client();
+	client->surface = create_test_surface(client);
+	client->surface->width = 10000; /* used only for damage */
+	client->surface->height = 10000;
+	client->surface->buffer = client_buffer_from_image_file(client,
+							"basic-test-card",
+							bargs->scale);
+	wl_surface_set_buffer_scale(client->surface->wl_surface, bargs->scale);
+	wl_surface_set_buffer_transform(client->surface->wl_surface,
+					bargs->transform);
+	move_client(client, 19, 19);
+
+	match = verify_screen_content(client, refname, 0, NULL, 0);
+	assert(match);
+
+	client_destroy(client);
+}