testsuite: Add stroke tests

Same as the recent fill tests, just with strokes.

testsuite/gsk/compare/stroke-opacity.node

@@ -0,0 +1,28 @@
+opacity {
+  child: stroke {
+    child: opacity {
+      opacity: 0.4;
+      child: color {
+        bounds: 0 0 50 50;
+        color: rgb(255,0,0);
+      }
+    }
+    path: "\
+M 15 5\
+L 35 5\
+L 35 15\
+L 45 15\
+L 45 35\
+L 35 35\
+L 35 45\
+L 15 45\
+L 15 35\
+L 5 35\
+L 5 15\
+L 15 15\
+Z";
+    line-width: 10;
+    line-cap: butt;
+    line-join: miter;
+  }
+}

testsuite/gsk/compare/stroke-with-3d-contents-nogl-nocairo.node

@@ -0,0 +1,26 @@
+stroke {
+  child: transform {
+    transform: translate3d(0, 0, 1);
+    child: color {
+      bounds: 0 0 50 50;
+      color: rgb(255,0,0);
+    }
+  }
+  path: "\
+M 15 5\
+L 35 5\
+L 35 15\
+L 45 15\
+L 45 35\
+L 35 35\
+L 35 45\
+L 15 45\
+L 15 35\
+L 5 35\
+L 5 15\
+L 15 15\
+Z";
+  line-width: 10;
+  line-cap: butt;
+  line-join: miter;
+}

testsuite/gsk/meson.build

@@ -117,6 +117,8 @@ compare_render_tests = [
   'shadow-opacity',
   'shrink-rounded-border',
   'stroke',
+  'stroke-opacity',
+  'stroke-with-3d-contents-nogl-nocairo',
   'texture-coords',
   'texture-scale-filters-nocairo',
   'texture-scale-magnify-10000x',