Add UI layout XML automation

tests/ui_core/layout_xml_tests.cpp

@@ -0,0 +1,47 @@
+#include "ui_core/layout_xml.h"
+#include "test_harness.h"
+
+using pp::foundation::StatusCode;
+using pp::ui::parse_layout_xml;
+
+namespace {
+
+void parses_nested_layout_xml_and_lengths(pp::tests::Harness& h)
+{
+    constexpr auto xml =
+        "<layout width=\"100%\" height=\"auto\">"
+        "  <panel width=\"320\" height=\"200\">"
+        "    <button width=\"64\" height=\"28\"/>"
+        "  </panel>"
+        "</layout>";
+
+    const auto summary = parse_layout_xml(xml);
+
+    PP_EXPECT(h, summary.ok());
+    PP_EXPECT(h, summary.value().node_count == 3U);
+    PP_EXPECT(h, summary.value().length_attribute_count == 6U);
+}
+
+void rejects_malformed_empty_and_invalid_lengths(pp::tests::Harness& h)
+{
+    const auto empty = parse_layout_xml("");
+    const auto malformed = parse_layout_xml("<layout><panel></layout>");
+    const auto invalid_length = parse_layout_xml("<layout width=\"101%\"/>");
+
+    PP_EXPECT(h, !empty.ok());
+    PP_EXPECT(h, empty.status().code == StatusCode::invalid_argument);
+    PP_EXPECT(h, !malformed.ok());
+    PP_EXPECT(h, malformed.status().code == StatusCode::invalid_argument);
+    PP_EXPECT(h, !invalid_length.ok());
+    PP_EXPECT(h, invalid_length.status().code == StatusCode::out_of_range);
+}
+
+}
+
+int main()
+{
+    pp::tests::Harness harness;
+    harness.run("parses_nested_layout_xml_and_lengths", parses_nested_layout_xml_and_lengths);
+    harness.run("rejects_malformed_empty_and_invalid_lengths", rejects_malformed_empty_and_invalid_lengths);
+    return harness.finish();
+}