Add enum support (#49)

tests/sqlite/test_enum_namespace.cpp

@@ -0,0 +1,62 @@
+#ifndef SQLGEN_BUILD_DRY_TESTS_ONLY
+
+#include <gtest/gtest.h>
+
+#include <rfl.hpp>
+#include <rfl/json.hpp>
+#include <sqlgen.hpp>
+#include <sqlgen/sqlite.hpp>
+#include <vector>
+
+namespace test_enum_namespace {
+namespace first {
+enum class IdenticallyNamed { VALUE0, VALUE1, VALUE2 };
+
+}
+namespace second {
+enum class IdenticallyNamed { VALUE3, VALUE4, VALUE5 };
+}
+
+struct MultiStruct {
+  sqlgen::PrimaryKey<uint32_t, sqlgen::auto_incr> id;
+  first::IdenticallyNamed enum_one;
+  second::IdenticallyNamed enum_two;
+};
+
+TEST(mysql, test_enum_namespace) {
+  using namespace sqlgen;
+  using namespace sqlgen::literals;
+
+  auto objects = std::vector<MultiStruct>({
+      MultiStruct{.enum_one = first::IdenticallyNamed::VALUE0,
+                  .enum_two = second::IdenticallyNamed::VALUE3},
+      MultiStruct{.enum_one = first::IdenticallyNamed::VALUE1,
+                  .enum_two = second::IdenticallyNamed::VALUE4},
+      MultiStruct{.enum_one = first::IdenticallyNamed::VALUE2,
+                  .enum_two = second::IdenticallyNamed::VALUE5},
+  });
+
+  const auto conn = sqlite::connect();
+  conn.and_then(drop<MultiStruct> | if_exists);
+
+  write(conn, objects);
+
+  const auto read_objects =
+      sqlgen::read<std::vector<MultiStruct>>(conn).value();
+  std::vector<uint32_t> actual_ids;
+  for (const auto& obj : read_objects) {
+    if (obj.enum_one == first::IdenticallyNamed::VALUE0) {
+      EXPECT_EQ(obj.enum_two, second::IdenticallyNamed::VALUE3);
+    } else if (obj.enum_one == first::IdenticallyNamed::VALUE1) {
+      EXPECT_EQ(obj.enum_two, second::IdenticallyNamed::VALUE4);
+    } else if (obj.enum_one == first::IdenticallyNamed::VALUE2) {
+      EXPECT_EQ(obj.enum_two, second::IdenticallyNamed::VALUE5);
+    } else {
+      FAIL() << "Unexpected enum value";
+    }
+  }
+}
+
+}  // namespace test_enum_namespace
+
+#endif