From bf59e881f3d4069d01e1dfad7c2cd8db54975763 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Fri, 2 Oct 2026 15:47:50 +0200
Subject: kstd: ring_buffer: add more iterator tests

---
 libs/kstd/kstd/ring_buffer.tests.cpp | 64 ++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/libs/kstd/kstd/ring_buffer.tests.cpp b/libs/kstd/kstd/ring_buffer.tests.cpp
index 12a88e8f..99dbe3eb 100644
--- a/libs/kstd/kstd/ring_buffer.tests.cpp
+++ b/libs/kstd/kstd/ring_buffer.tests.cpp
@@ -1047,6 +1047,70 @@ SCENARIO("Ring Buffer iterators", "[kstd][ring_buffer]")
 
       REQUIRE(it == buffer.crend());
     }
+
+    THEN("a const_iterator can be constructed from an iterator")
+    {
+      auto it = decltype(buffer)::const_iterator{buffer.begin()};
+
+      AND_THEN("the const_iterator points to the same element as the original iterator")
+      {
+        REQUIRE(*it == *buffer.begin());
+      }
+    }
+
+    THEN("two iterators constructed from begin() and cbegin() compare equal")
+    {
+      auto it = buffer.begin();
+      auto cit = buffer.cbegin();
+
+      REQUIRE(it == cit);
+    }
+
+    THEN("an iterator to the second element compares greater than begin()")
+    {
+      REQUIRE(++buffer.begin() > buffer.begin());
+    }
+
+    THEN("an iterator to the second element compares less than the iterator to the third element")
+    {
+      REQUIRE(++buffer.begin() < std::next(buffer.begin(), 2));
+    }
+
+    THEN("the adding 1 to the iterator returned by begin() yields an iterator to the second element")
+    {
+      REQUIRE((buffer.begin() + 1) == ++buffer.begin());
+      REQUIRE((1 + buffer.begin()) == ++buffer.begin());
+    }
+
+    THEN("subtracting 1 from the iterator returned by the second element yields an iterator to the first element")
+    {
+      REQUIRE(((buffer.begin() + 1) - 1) == buffer.begin());
+    }
+
+    THEN("postfix incrementing the iterator returned by begin() yields an iterator to the first element")
+    {
+      REQUIRE(buffer.begin()++ == buffer.begin());
+    }
+
+    THEN("postfix decrementing the iterator one after begin() yields an iterator to the first element")
+    {
+      REQUIRE((buffer.begin() + 1)-- == (buffer.begin() + 1));
+    }
+
+    THEN("accessing an element by subscripting the iterator yields the correct element")
+    {
+      auto it = buffer.begin();
+      REQUIRE(std::addressof(it[0]) == std::addressof(buffer.at(0)));
+      REQUIRE(std::addressof(it[1]) == std::addressof(buffer.at(1)));
+      REQUIRE(std::addressof(it[2]) == std::addressof(buffer.at(2)));
+    }
+
+    THEN("access to an element via member-of-pointer yields the correct element")
+    {
+      auto it = buffer.begin();
+      REQUIRE(it.operator->() == std::addressof(buffer.at(0)));
+    }
+
     WHEN("working through a const reference")
     {
       auto const & ref = buffer;
-- 
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