tests: Add line-width-tolerance

Test case taken from the WebKit test suite, failure originally reported
by Zan Dobersek <zandobersek@gmail.com> at
https://bugs.webkit.org/show_bug.cgi?id=54471

test/Makefile.sources

@@ -150,6 +150,7 @@ test_sources = \
 	leaky-polygon.c					\
 	line-width.c					\
 	line-width-scale.c				\
+	line-width-tolerance.c				\
 	line-width-zero.c				\
 	linear-gradient.c				\
 	linear-gradient-extend.c			\

test/line-width-tolerance.c

@@ -0,0 +1,66 @@
+/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
+/*
+ * Copyright 2011 Red Hat Inc.
+ *
+ * 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.
+ *
+ * Author: Benjamin Otte <otte@redhat.com>
+ */
+
+/*
+ * Test case taken from the WebKit test suite, failure originally reported
+ * by Zan Dobersek <zandobersek@gmail.com> at
+ * https://bugs.webkit.org/show_bug.cgi?id=54471
+ */
+
+#include "cairo-test.h"
+
+#include <math.h>
+
+#define RADIUS 50
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    /* fill with green so RGB and RGBA tests can share the ref image */
+    cairo_set_source_rgb (cr, 0, 1, 0);
+    cairo_paint (cr);
+
+    /* red to see eventual bugs immediately */
+    cairo_set_source_rgb (cr, 1, 0, 0);
+
+    /* stroke 3/4 of a circle where the last quarter would be this
+     * reference image. Keep just a 1 pixel border. Use a huge line
+     * width (twice the circle's radius to get it filled completely).
+     */
+    cairo_set_line_width (cr, 2 * RADIUS);
+    cairo_arc (cr, 1, RADIUS - 1, RADIUS, 0, - M_PI / 2.0);
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (line_width_tolerance,
+	    "Test interaction of line width and tolerance when stroking arcs",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    RADIUS, RADIUS,
+	    NULL, draw)