New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/base/base_tests/visitor_tests.cpp

@@ -0,0 +1,45 @@
+#include "testing/testing.hpp"
+
+#include "base/visitor.hpp"
+
+#include <string>
+
+using namespace std;
+
+namespace
+{
+struct Foo
+{
+  DECLARE_VISITOR()
+  DECLARE_DEBUG_PRINT(Foo)
+};
+
+struct Bar
+{
+  Bar() = default;
+  Bar(int d, string const & s) : m_d(d), m_s(s) {}
+
+  DECLARE_VISITOR(visitor(m_d), visitor(m_s, "string"))
+  DECLARE_DEBUG_PRINT(Bar)
+
+  int m_d = 0;
+  string m_s;
+};
+
+UNIT_TEST(DebugPrintVisitor_Smoke)
+{
+  {
+    Foo foo;
+    TEST_EQUAL(DebugPrint(foo), "Foo []", ());
+  }
+
+  {
+    Bar bar;
+    TEST_EQUAL(DebugPrint(bar), "Bar [0, string: ]", ());
+
+    bar.m_d = 7;
+    bar.m_s = "Hello, World!";
+    TEST_EQUAL(DebugPrint(bar), "Bar [7, string: Hello, World!]", ());
+  }
+}
+}  // namespace