Feature: the Modal component. (#418)

src/ftxui/component/modal_test.cpp

@@ -0,0 +1,47 @@
+#include <gtest/gtest-message.h>  // for Message
+#include <gtest/gtest-test-part.h>  // for SuiteApiResolver, TestPartResult, TestFactoryImpl
+#include <ftxui/dom/elements.hpp>  // for Element, operator|, text, border
+#include <memory>  // for shared_ptr, allocator, __shared_ptr_access
+
+#include "ftxui/component/component.hpp"       // for Renderer, Modal
+#include "ftxui/component/component_base.hpp"  // for ComponentBase
+#include "ftxui/dom/node.hpp"                  // for Render
+#include "ftxui/screen/screen.hpp"             // for Screen
+#include "gtest/gtest_pred_impl.h"             // for Test, EXPECT_EQ, TEST
+
+namespace ftxui {
+
+TEST(ModalTest, Basic) {
+  auto main = Renderer([] { return text("main") | border; });
+  auto modal = Renderer([] { return text("modal") | border; });
+  bool show_modal = false;
+  auto component = Modal(main, modal, &show_modal);
+
+  Screen screen(10, 7);
+  Render(screen, component->Render());
+  EXPECT_EQ(screen.ToString(),
+            "╭────────╮\r\n"
+            "│main    │\r\n"
+            "│        │\r\n"
+            "│        │\r\n"
+            "│        │\r\n"
+            "│        │\r\n"
+            "╰────────╯");
+
+  show_modal = true;
+  Render(screen, component->Render());
+  EXPECT_EQ(screen.ToString(),
+            "╭────────╮\r\n"
+            "│main    │\r\n"
+            "│╭─────╮ │\r\n"
+            "││modal│ │\r\n"
+            "│╰─────╯ │\r\n"
+            "│        │\r\n"
+            "╰────────╯");
+}
+
+}  // namespace ftxui
+
+// Copyright 2022 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.