build: Move tests/reftests to testsuite/reftests

testsuite/reftests/background-area.css

@@ -0,0 +1,59 @@
+* {
+  engine: none;
+  border-style: none;
+  border-image: none;
+  background-image: none;
+  background-clip: border-box;
+  border-radius: 0;
+}
+
+GtkWindow {
+  background-color: rgb(0,255,0);
+}
+
+GtkButton {
+  border-width: 5px;
+  border-style: solid;
+  border-color: rgba(255,0,0,0.6);
+  padding: 10px;
+  background-color: rgb(0,0,255);
+
+  /* Make sure children of button are only offset by padding */
+  -GtkButton-default-border: 0;
+  -GtkButton-inner-border: 0;
+  -GtkWidget-focus-line-width: 0;
+  -GtkWidget-focus-padding: 0;
+}
+
+#button1 {
+  background-clip: border-box;
+}
+
+#button2 {
+  background-clip: padding-box;
+}
+
+#button3 {
+  background-clip: content-box;
+}
+
+#reference1 {
+  border-color: rgb(153,0,102);
+}
+
+#reference2 {
+  border-color: rgb(153,102,0);
+}
+
+#reference3 {
+  border-color: rgb(153,102,0);
+  background-color: transparent;
+}
+
+#reference3inner {
+  padding: 0;
+  border-width: 0;
+  border-color: rgb(0, 255, 0);
+  background-color: rgb(0,0,255);
+}
+