kstd/observer_ptr: extend test suite

2 files changed, 149 insertions, 24 deletions

diff --git a/libs/kstd/include/kstd/observer_ptr b/libs/kstd/include/kstd/observer_ptr
index 97c9e5e..a328331 100644
--- a/libs/kstd/include/kstd/observer_ptr
+++ b/libs/kstd/include/kstd/observer_ptr
@@ -85,7 +85,7 @@ namespace kstd
     //! Get the currently watched object.
     //!
     //! @return A reference to the currently watched object.
-    [[nodiscard]] constexpr auto operator*() const noexcept -> std::add_lvalue_reference_t<element_type>
+    [[nodiscard]] constexpr auto operator*() const -> std::add_lvalue_reference_t<element_type>
     {
       throw_on_null();
       return *m_ptr;
@@ -94,7 +94,7 @@ namespace kstd
     //! Get the currently watched object.
     //!
     //! @return A pointer to the currently watched object.
-    [[nodiscard]] constexpr auto operator->() const noexcept -> element_type *
+    [[nodiscard]] constexpr auto operator->() const -> element_type *
     {
       throw_on_null();
       return m_ptr;
@@ -109,7 +109,7 @@ namespace kstd
     }
 
     //! Compare the observer pointer with another observer pointer.
-    //!
+    //!>
     //! @param other The other observer pointer to compare with.
     //! @return The result of the comparison.
     constexpr auto operator<=>(observer_ptr const & other) const noexcept -> std::strong_ordering = default;
@@ -118,7 +118,7 @@ namespace kstd
     //! Throw an exception if the observer pointer is null.
     //!
     //! @throws std::runtime_error if the observer pointer is null.
-    constexpr auto throw_on_null() const noexcept -> void
+    constexpr auto throw_on_null() const -> void
     {
       if (m_ptr == nullptr)
       {
diff --git a/libs/kstd/tests/src/observer_ptr.cpp b/libs/kstd/tests/src/observer_ptr.cpp
index 2fe2226..5d94098 100644
--- a/libs/kstd/tests/src/observer_ptr.cpp
+++ b/libs/kstd/tests/src/observer_ptr.cpp
@@ -3,8 +3,28 @@
 
 #include <catch2/catch_test_macros.hpp>
 
+#include <compare>
+#include <type_traits>
 #include <utility>
 
+namespace
+{
+  struct Base
+  {
+  };
+
+  struct Derived : Base
+  {
+  };
+
+  struct Element
+  {
+    int value{};
+
+    constexpr auto operator<=>(Element const &) const noexcept = default;
+  };
+}  // namespace
+
 SCENARIO("Observer Pointer initialization and construction", "[observer_ptr]")
 {
   GIVEN("An empty context")
@@ -59,17 +79,9 @@ SCENARIO("Observer Pointer initialization and construction", "[observer_ptr]")
 
     WHEN("copy constructing from an existing observer pointer with a compatible type")
     {
-      struct A
-      {
-      };
-
-      struct B : A
-      {
-      };
-
-      auto value = B{};
-      auto ptr = kstd::observer_ptr<B>(&value);
-      auto copy = kstd::observer_ptr<A>(ptr);
+      auto value = Derived{};
+      auto ptr = kstd::observer_ptr<Derived>(&value);
+      kstd::observer_ptr<Base> copy = ptr;
 
       THEN("the new observer pointer points to the same object as the other observer pointer")
       {
@@ -112,6 +124,22 @@ SCENARIO("Observer Pointer initialization and construction", "[observer_ptr]")
         REQUIRE(&*copy == &value);
       }
     }
+
+    WHEN("constructing an observer pointer using make_observer")
+    {
+      auto value = 1;
+      auto ptr = kstd::make_observer(&value);
+
+      THEN("the observer pointer points to the correct object")
+      {
+        REQUIRE(&*ptr == &value);
+      }
+
+      THEN("the observe pointer has the correct element type")
+      {
+        STATIC_REQUIRE(std::is_same_v<decltype(ptr), kstd::observer_ptr<int>>);
+      }
+    }
   }
 }
 
@@ -174,6 +202,24 @@ SCENARIO("Observer pointer modifiers", "[observer_ptr]")
         REQUIRE(&*other_ptr == &value);
       }
     }
+
+    WHEN("using namespace-level swap to swap it with another observer pointer")
+    {
+      using std::swap;
+      auto other_value = 2;
+      auto other_ptr = kstd::observer_ptr{&other_value};
+      swap(ptr, other_ptr);
+
+      THEN("the observer pointer points to the other object")
+      {
+        REQUIRE(&*ptr == &other_value);
+      }
+
+      THEN("the other observer pointer points to the original object")
+      {
+        REQUIRE(&*other_ptr == &value);
+      }
+    }
   }
 }
 
@@ -181,14 +227,7 @@ SCENARIO("Observer pointer observers", "[observer_ptr]")
 {
   GIVEN("A non-null observer pointer")
   {
-    struct A
-    {
-      int value{};
-
-      constexpr auto operator<=>(A const & other) const noexcept = default;
-    };
-
-    auto value = A{1};
+    auto value = Element{1};
     auto ptr = kstd::observer_ptr{&value};
 
     WHEN("getting the raw pointer")
@@ -223,12 +262,98 @@ SCENARIO("Observer pointer observers", "[observer_ptr]")
 
     WHEN("converting the observer pointer to a raw pointer")
     {
-      auto raw_ptr = static_cast<A *>(ptr);
+      auto raw_ptr = static_cast<Element *>(ptr);
 
       THEN("the raw pointer points to the correct object")
       {
         REQUIRE(raw_ptr == &value);
       }
     }
+
+    WHEN("checking the observer pointer as a boolean")
+    {
+      THEN("it returns true")
+      {
+        REQUIRE(static_cast<bool>(ptr));
+      }
+    }
+  }
+
+  GIVEN("A null observer pointer")
+  {
+    auto ptr = kstd::observer_ptr<Element>{};
+
+    WHEN("checking the observer pointer as a boolean")
+    {
+      THEN("it returns false")
+      {
+        REQUIRE_FALSE(static_cast<bool>(ptr));
+      }
+    }
+
+    WHEN("dereferencing the observer pointer")
+    {
+      THEN("the observer pointer panics")
+      {
+        REQUIRE_THROWS_AS(*ptr, kstd::tests::os_panic);
+      }
+    }
+
+    WHEN("writing through the observer pointer with the arrow operator")
+    {
+      THEN("the observer pointer panics")
+      {
+        REQUIRE_THROWS_AS(ptr->value = 2, kstd::tests::os_panic);
+      }
+    }
+  }
+}
+
+SCENARIO("Observer pointer comparisons", "[observer_ptr]")
+{
+  GIVEN("Observer pointers to elements of an array")
+  {
+    int arr[] = {1, 2};
+    auto ptr1 = kstd::observer_ptr{&arr[0]};
+    auto ptr2 = kstd::observer_ptr{&arr[1]};
+
+    WHEN("comparing the same observer pointer")
+    {
+      THEN("they are equal")
+      {
+        REQUIRE(ptr1 == ptr1);
+        REQUIRE((ptr1 <=> ptr1) == std::strong_ordering::equal);
+      }
+    }
+
+    WHEN("comparing different observer pointers")
+    {
+      THEN("they are ordered correctly")
+      {
+        REQUIRE(ptr1 != ptr2);
+        REQUIRE(ptr1 < ptr2);
+        REQUIRE(ptr1 <= ptr2);
+        REQUIRE(ptr2 > ptr1);
+        REQUIRE(ptr2 >= ptr1);
+        REQUIRE((ptr1 <=> ptr2) == std::strong_ordering::less);
+        REQUIRE((ptr2 <=> ptr1) == std::strong_ordering::greater);
+      }
+    }
+  }
+
+  GIVEN("A null observer pointer")
+  {
+    auto ptr = kstd::observer_ptr<int>{};
+
+    WHEN("comparing with another null observer pointer")
+    {
+      auto other_ptr = kstd::observer_ptr<int>{};
+
+      THEN("they are equal")
+      {
+        REQUIRE(ptr == other_ptr);
+        REQUIRE((ptr <=> other_ptr) == std::strong_ordering::equal);
+      }
+    }
   }
 }
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