kernel/tests: prevent double mapping of pages

1 files changed, 6 insertions, 1 deletions

diff --git a/kernel/src/test_support/page_mapper.cpp b/kernel/src/test_support/page_mapper.cpp
index 805998b..abdcae5 100644
--- a/kernel/src/test_support/page_mapper.cpp
+++ b/kernel/src/test_support/page_mapper.cpp
@@ -18,7 +18,12 @@ namespace kernel::tests
 
   auto page_mapper::map(kapi::memory::page page, kapi::memory::frame frame, flags) -> std::byte *
   {
-    page_mappings.insert({page.number(), frame});
+    auto result = page_mappings.insert({page.number(), frame});
+    if (!result.second)
+    {
+      auto error = std::format("Page {} was already mapped!", page.number());
+      throw std::invalid_argument{error};
+    }
 
     auto page_address = page.start_address();
     auto sandbox_start = memory.heap_base();