Improve tests for assign in std::vector

Author: winner245

libcxx/test/std/containers/sequences/vector/vector.cons/assign_iter_iter.pass.cpp

@@ -18,17 +18,16 @@
 #include "asan_testing.h"
 #include "test_iterators.h"
 #if TEST_STD_VER >= 11
-#include "emplace_constructible.h"
-#include "container_test_types.h"
+#  include "emplace_constructible.h"
+#  include "container_test_types.h"
 #endif
 
-
 TEST_CONSTEXPR_CXX20 bool test() {
 #if TEST_STD_VER >= 11
   int arr1[] = {42};
   int arr2[] = {1, 101, 42};
-  {
-    using T = EmplaceConstructibleMoveableAndAssignable<int>;
+  { // Test with new_size > capacity() == 0 for forward_iterator, resulting in reallocation during assign
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
     using It = forward_iterator<int*>;
     {
       std::vector<T> v;
@@ -43,8 +42,8 @@ TEST_CONSTEXPR_CXX20 bool test() {
       assert(v[2].value == 42);
     }
   }
-  {
-    using T = EmplaceConstructibleMoveableAndAssignable<int>;
+  { // Test with new_size > capacity() == 0 for input_iterator, resulting in reallocation during assign
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
     using It = cpp17_input_iterator<int*>;
     {
       std::vector<T> v;
@@ -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
+    using T  = EmplaceConstructibleMoveableAndAssignable<int>;
+    using It = cpp17_input_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);
+    }
+  }
 #endif
 
   // Test with a number of elements in the source range that is greater than capacity