[libcxx-commits] [libcxx] [libc++][test] Improve tests for assign in std::vector (PR #119163)

[Louis Dionne via libcxx-commits]

================
@@ -63,6 +62,100 @@ TEST_CONSTEXPR_CXX20 bool test() {
       assert(v[2].value == 42);
     }
   }
+
+  { // Test with new_size < size() for forward_iterator, resulting in destruction at end during assign
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
+    using It = forward_iterator<int*>;
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      for (std::size_t i = 0; i < v.capacity(); ++i)
+        v.emplace_back(99);
+      v.assign(It(arr1), It(std::end(arr1)));
+      assert(v.size() == 1);
+      assert(v[0].value == 42);
+    }
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      for (std::size_t i = 0; i < v.capacity(); ++i)
+        v.emplace_back(99);
+      v.assign(It(arr2), It(std::end(arr2)));
+      assert(v.size() == 3);
+      assert(v[0].value == 1);
+      assert(v[1].value == 101);
+      assert(v[2].value == 42);
+    }
+  }
+  { // Test with new_size < size() for input_iterator, resulting in destruction at end during assign
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
+    using It = cpp17_input_iterator<int*>;
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      for (std::size_t i = 0; i < v.capacity(); ++i)
+        v.emplace_back(99);
+      v.assign(It(arr1), It(std::end(arr1)));
+      assert(v.size() == 1);
+      assert(v[0].value == 42);
+    }
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      for (std::size_t i = 0; i < v.capacity(); ++i)
+        v.emplace_back(99);
+      v.assign(It(arr2), It(std::end(arr2)));
+      assert(v.size() == 3);
+      assert(v[0].value == 1);
+      assert(v[1].value == 101);
+      assert(v[2].value == 42);
+    }
+  }
+
+  { // Test with size() < new_size < capacity() for forward_iterator, resulting in construction at end during assign
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
+    using It = forward_iterator<int*>;
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      v.assign(It(arr1), It(std::end(arr1)));
+      assert(v.size() == 1);
+      assert(v[0].value == 42);
+    }
+    {
+      std::vector<T> v;
+      v.reserve(5);
+      for (std::size_t i = 0; i < 2; ++i)
+        v.emplace_back(99);
+      v.assign(It(arr2), It(std::end(arr2)));
+      assert(v.size() == 3);
+      assert(v[0].value == 1);
+      assert(v[1].value == 101);
+      assert(v[2].value == 42);
+    }
+  }
+  { // Test with size() < new_size < capacity() for inputs_iterator, resulting in construction at end during assign
----------------
ldionne wrote:

```suggestion
  { // Test with size() < new_size < capacity() for input_iterator, resulting in construction at end during assign
```

https://github.com/llvm/llvm-project/pull/119163