test: Add a1-bug

Capture a bug report from "cairouser" where a1 rasterisation is now
broken.

test/Makefile.am

@@ -131,6 +131,9 @@ CLEANFILES += $(BUILT_SOURCES)
 
 # All tests which have a reference image go here.
 REFERENCE_IMAGES = \
+	a1-bug.ref.png \
+	a1-bug.image16.ref.png \
+	a1-bug.xlib.ref.png \
 	a1-image-sample.ref.png \
 	a1-image-sample.gl.xfail.png \
 	a1-image-sample.quartz.xfail.png \

test/Makefile.sources

@@ -1,4 +1,5 @@
 test_sources = \
+	a1-bug.c					\
 	a1-image-sample.c 				\
 	a1-mask.c					\
 	a1-mask-sample.c 				\

test/a1-bug.c

@@ -0,0 +1,61 @@
+/*
+ * 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 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 "cairo-test.h"
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    static const struct point {
+	double x;
+	double y;
+    } xy[] = {
+	{ 627.016212, 221.749777 },
+	{ 756.120787, 221.749777 },
+	{ 756.120787, 557.602766 },
+	{ 626.952721, 557.602766 },
+	{ 626.548456, 493.315729 },
+    };
+    unsigned int i;
+
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_paint (cr);
+
+    for (i = 0; i < sizeof (xy) / sizeof (xy[0]); i++)
+	cairo_line_to (cr, xy[i].x, xy[i].y);
+
+    cairo_set_source_rgb (cr, 1, 0, 0);
+    cairo_fill_preserve (cr);
+
+    cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
+    cairo_set_source_rgb (cr, 0, 1, 0);
+    cairo_fill (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (a1_bug,
+	    "Check the fidelity of the rasterisation.",
+	    "a1 raster", /* keywords */
+	    "target=raster", /* requirements */
+	    1000, 800,
+	    NULL, draw)