From 338d9b2b6fc517df2135089699234232495324d6 Mon Sep 17 00:00:00 2001
From: Felix Morgner <felix.morgner@ost.ch>
Date: Fri, 1 May 2026 13:11:37 +0200
Subject: kstd/vector: improve append_range tests

---
 libs/kstd/tests/include/kstd/tests/test_types.hpp | 27 +++++++-
 libs/kstd/tests/src/vector.cpp                    | 77 +++++++++++++++++++++--
 2 files changed, 98 insertions(+), 6 deletions(-)

(limited to 'libs/kstd')

diff --git a/libs/kstd/tests/include/kstd/tests/test_types.hpp b/libs/kstd/tests/include/kstd/tests/test_types.hpp
index 9207ee9..8231fd3 100644
--- a/libs/kstd/tests/include/kstd/tests/test_types.hpp
+++ b/libs/kstd/tests/include/kstd/tests/test_types.hpp
@@ -239,17 +239,29 @@ namespace kstd::tests
   struct test_input_iterator
   {
     using iterator_concept = std::input_iterator_tag;
+    using iterator_category = std::input_iterator_tag;
     using difference_type = std::ptrdiff_t;
     using value_type = int;
+    using reference = int const &;
+    using pointer = int const *;
 
     //! The current element pointed to by the iterator.
     int const * current;
+    //! The number of elements in the range.
+    std::size_t count;
+
+    explicit test_input_iterator()
+        : current{nullptr}
+        , count{0}
+    {}
 
     //! Construct a new test input iterator.
     //!
     //! @param current The current element pointed to by the iterator.
-    constexpr explicit test_input_iterator(int const * current)
+    //! @param count The number of elements in the range.
+    explicit test_input_iterator(int const * current, std::size_t count)
         : current{current}
+        , count{count}
     {}
 
     //! Dereference the iterator to get the current element.
@@ -266,6 +278,7 @@ namespace kstd::tests
     auto operator++() -> test_input_iterator &
     {
       ++current;
+      --count;
       return *this;
     }
 
@@ -281,7 +294,17 @@ namespace kstd::tests
     //! @return True if the two test input iterators are equal, false otherwise.
     [[nodiscard]] auto operator==(test_input_iterator const & other) const -> bool
     {
-      return current == other.current;
+      if (current == nullptr && other.current == nullptr)
+      {
+        return true;
+      }
+
+      if (current == nullptr || other.current == nullptr)
+      {
+        return count == other.count;
+      }
+
+      return current == other.current && count == other.count;
     }
   };
 
diff --git a/libs/kstd/tests/src/vector.cpp b/libs/kstd/tests/src/vector.cpp
index edf47d7..a02ebf0 100644
--- a/libs/kstd/tests/src/vector.cpp
+++ b/libs/kstd/tests/src/vector.cpp
@@ -522,16 +522,77 @@ SCENARIO("Vector modifiers", "[vector]")
       auto const range = std::views::iota(0, 3);
       v.append_range(range);
 
-      THEN("the size and capacity increase and the elements are appended")
+      THEN("the size increases")
       {
         REQUIRE(v.size() == 3);
+      }
+
+      THEN("the capacity increases")
+      {
         REQUIRE(v.capacity() >= 3);
+      }
+
+      THEN("the elements are appended")
+      {
         REQUIRE(v[0] == 0);
         REQUIRE(v[1] == 1);
         REQUIRE(v[2] == 2);
       }
     }
 
+    WHEN("appending from an input range")
+    {
+      auto const arr = std::array<int, 3>{1, 2, 3};
+      auto const first = kstd::tests::test_input_iterator{arr.data(), arr.size()};
+      auto const last = kstd::tests::test_input_iterator{};
+
+      v.append_range(std::ranges::subrange{first, last});
+
+      THEN("the size increases")
+      {
+        REQUIRE(v.size() == 3);
+      }
+
+      THEN("the capacity increases")
+      {
+        REQUIRE(v.capacity() >= 3);
+      }
+
+      THEN("the elements are appended")
+      {
+        REQUIRE(v[0] == 1);
+        REQUIRE(v[1] == 2);
+        REQUIRE(v[2] == 3);
+      }
+    }
+
+    WHEN("appending from an input range with sufficient capacity")
+    {
+      v.reserve(3);
+      auto const arr = std::array<int, 3>{1, 2, 3};
+      auto const first = kstd::tests::test_input_iterator{arr.data(), arr.size()};
+      auto const last = kstd::tests::test_input_iterator{};
+
+      v.append_range(std::ranges::subrange{first, last});
+
+      THEN("the size increases")
+      {
+        REQUIRE(v.size() == 3);
+      }
+
+      THEN("the capacity stays the same")
+      {
+        REQUIRE(v.capacity() == 3);
+      }
+
+      THEN("the elements are appended")
+      {
+        REQUIRE(v[0] == 1);
+        REQUIRE(v[1] == 2);
+        REQUIRE(v[2] == 3);
+      }
+    }
+
     WHEN("resizing the vector to a greater size")
     {
       v.resize(3);
@@ -881,10 +942,18 @@ SCENARIO("Vector modifiers", "[vector]")
       auto initial_size = v.size();
       v.append_range(std::views::iota(0, 3));
 
-      THEN("capacity and size are increased and the elements are appended")
+      THEN("capacity is increased")
       {
         REQUIRE(v.capacity() >= initial_capacity);
+      }
+
+      THEN("size is increased")
+      {
         REQUIRE(v.size() == initial_size + 3);
+      }
+
+      THEN("the elements are appended")
+      {
         REQUIRE(v[initial_size + 0] == 0);
         REQUIRE(v[initial_size + 1] == 1);
         REQUIRE(v[initial_size + 2] == 2);
@@ -1290,8 +1359,8 @@ SCENARIO("Vector advanced construction", "[vector]")
     WHEN("constructing from input iterators")
     {
       auto const arr = std::array<int, 3>{1, 2, 3};
-      auto const first = kstd::tests::test_input_iterator{arr.data()};
-      auto const last = kstd::tests::test_input_iterator{arr.data() + arr.size()};
+      auto const first = kstd::tests::test_input_iterator{arr.data(), arr.size()};
+      auto const last = kstd::tests::test_input_iterator{};
 
       auto v = kstd::vector<int>(first, last);
 
-- 
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