tests: add viewport test for repeat mode

This test ensures that
	"pixman-renderer: half-fix bilinear sampling on edges"
keeps on working.

Unlike in the original report
https://gitlab.freedesktop.org/wayland/weston/issues/373, here we use buffer
scale 2 instead of output scale 2 to trigger bilinear filter. The effect is the
same, the actual resulting image in the failing case is just a little
different. This is so that it will be easy to add more viewport screenshooting
tests in this program in the future.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/meson.build

@@ -185,6 +185,7 @@ tests = [
 		'dep_objs': dep_vertex_clipping,
 	},
 	{	'name': 'viewporter', },
+	{	'name': 'viewporter-shot', },
 ]
 
 tests_standalone = [

tests/viewporter-shot-test.c

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2014, 2016, 2020 Collabora, Ltd.
+ * Copyright 2020 Zodiac Inflight Innovations
+ *
+ * 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"
+
+static const enum renderer_type renderers[] = {
+	RENDERER_PIXMAN,
+	RENDERER_GL,
+};
+
+static enum test_result_code
+fixture_setup(struct weston_test_harness *harness,
+	      const enum renderer_type *renderer)
+{
+	struct compositor_setup setup;
+
+	compositor_setup_defaults(&setup);
+	setup.renderer = *renderer;
+	setup.shell = SHELL_TEST_DESKTOP;
+
+	return weston_test_harness_execute_as_client(harness, &setup);
+}
+DECLARE_FIXTURE_SETUP_WITH_ARG(fixture_setup, renderers);
+
+
+TEST(viewport_upscale_solid)
+{
+	struct client *client;
+	struct wp_viewport *viewport;
+	pixman_color_t color;
+	const int width = 256;
+	const int height = 100;
+	bool match;
+
+	color_rgb888(&color, 255, 128, 0);
+
+	client = create_client();
+	client->surface = create_test_surface(client);
+	viewport = client_create_viewport(client);
+
+	client->surface->buffer = create_shm_buffer_a8r8g8b8(client, 2, 2);
+	fill_image_with_color(client->surface->buffer->image, &color);
+
+	/* Needs output scale != buffer scale to hit bilinear filter. */
+	wl_surface_set_buffer_scale(client->surface->wl_surface, 2);
+
+	wp_viewport_set_destination(viewport, width, height);
+	client->surface->width = width;
+	client->surface->height = height;
+
+	move_client(client, 19, 19);
+
+	match = verify_screen_content(client, "viewport_upscale_solid", 0,
+				      NULL, 0);
+	assert(match);
+
+	wp_viewport_destroy(viewport);
+	client_destroy(client);
+}