Update unit-ordered_map-2.cpp

Added test for iterator consistency

Signed-off-by: Andrea Cocito <39852324+puffetto@users.noreply.github.com>

Author: puffetto

tests/src/unit-ordered_map-2.cpp

@@ -160,3 +160,40 @@ TEST_CASE("ordered_map with const and iteration consistency")
     }
     CHECK(keys == std::vector<int>{1,2});
 }
+
+TEST_CASE("ordered_map iterator stability")
+{
+    ordered_map<std::string, int> m;
+    m["a"] = 1;
+    m["b"] = 2;
+    m["c"] = 3;
+
+    auto ita = m.find("a");
+    REQUIRE(ita != m.end());
+    CHECK(ita->second == 1);
+
+    SECTION("iterator survives insertion of other keys")
+    {
+        m["d"] = 4;
+        m["e"] = 5;
+        CHECK(ita->first == "a");
+        CHECK(ita->second == 1);
+    }
+
+    SECTION("iterator survives erase of different key")
+    {
+        CHECK(m.erase("b") == 1);
+        CHECK(ita->first == "a");
+        CHECK(ita->second == 1);
+        CHECK(m.find("b") == m.end());
+    }
+
+    SECTION("iterator invalidated when its own key is erased")
+    {
+        // safe pattern: erase returns next iterator
+        auto next = m.erase(ita);
+        CHECK(next != m.end());
+        CHECK(next->first == "b"); // next element after "a"
+        CHECK(m.find("a") == m.end());
+    }
+}