Add code coverage support. (#378)

src/ftxui/dom/gauge_test.cpp

@@ -8,8 +8,7 @@
 #include "ftxui/screen/screen.hpp"  // for Screen
 #include "gtest/gtest_pred_impl.h"  // for Test, EXPECT_EQ, TEST
 
-using namespace ftxui;
-using namespace ftxui;
+namespace ftxui {
 
 TEST(GaugeTest, ZeroHorizontal) {
   auto root = gauge(0);
@@ -24,7 +23,11 @@ TEST(GaugeTest, HalfHorizontal) {
   Screen screen(11, 1);
   Render(screen, root);
 
+#if defined(FTXUI_MICROSOFT_TERMINAL_FALLBACK)
+  EXPECT_EQ("█████▌     ", screen.ToString());
+#else
   EXPECT_EQ("█████▍     ", screen.ToString());
+#endif
 }
 
 TEST(GaugeTest, OneHorizontal) {
@@ -95,6 +98,8 @@ TEST(GaugeTest, OneVertical) {
       screen.ToString());
 }
 
+}  // namespace ftxui
+
 // Copyright 2020 Arthur Sonzogni. All rights reserved.
 // Use of this source code is governed by the MIT license that can be found in
 // the LICENSE file.