test(vector): add assertions and fix minor issues in test suite

- Add <cassert> includes and comprehensive assert() checks to all
  vector container tests, verifying size, capacity, element values,
  and state after operations (push_back, pop_back, erase, insert,
  assign, swap, clear, shrink_to_fit, etc.)
- Fix typo in back.cc: "The first character" -> "The last character"
- Fix missing trailing newlines in multiple files
- Enable previously disabled append_range.cc test (remove #if 0)
- Add state assertions to shared_ptr index tests for insert_index
  and erase_index operations

Author: SekaiArendelle

tests/0026.container/0001.vector/append_range.cc

@@ -8,10 +8,8 @@ using namespace fast_io::mnp;
 
 int main()
 {
-#if 0
 	auto head = fast_io::vector<int>{1, 2, 3, 4};
 	auto const tail = std::list{-5, -6, -7};
 	head.append_range(tail);
 	assert(std::ranges::equal(head, fast_io::vector<int>{1, 2, 3, 4, -5, -6, -7}));
-#endif
-}
+}

tests/0026.container/0001.vector/assign.cc

@@ -1,4 +1,5 @@
-#include <string>
+#include <cassert>
+#include <string>
 #include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
@@ -18,6 +19,11 @@ int main()
 	};
 
 	characters.assign(5, 'a');
+	assert(characters.size() == 5);
+	for (char c : characters)
+	{
+		assert(c == 'a');
+	}
 	print_vector();
 
 #if 0

tests/0026.container/0001.vector/back.cc

@@ -1,4 +1,5 @@
-#include <fast_io.h>
+#include <cassert>
+#include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
 using namespace fast_io::mnp;
@@ -9,6 +10,7 @@ int main()
 
 	if (!letters.empty())
 	{
-		print("The first character is '", chvw(letters.back()), "'.\n");
+		print("The last character is '", chvw(letters.back()), "'.\n");
 	}
-}
+	assert(letters.back() == 'f');
+}

tests/0026.container/0001.vector/begin.cc

@@ -1,4 +1,5 @@
-#include <algorithm>
+#include <cassert>
+#include <algorithm>
 #include <numeric>
 #include <string>
 #include <fast_io.h>
@@ -17,17 +18,20 @@ int main()
 	print("\n");
 
 	// Sums all integers in the vector nums (if any), printing only the result.
-	println("Sum of nums: ",
-			std::accumulate(nums.begin(), nums.end(), 0));
+	auto const sum = std::accumulate(nums.begin(), nums.end(), 0);
+	println("Sum of nums: ", sum);
+	assert(sum == 31);
 
 	// Prints the first fruit in the vector fruits, checking if there is any.
 	if (!fruits.empty())
 	{
 		println("First fruit: ", *fruits.begin());
+		assert(*fruits.begin() == "orange");
 	}
 
 	if (empty.begin() == empty.end())
 	{
 		print("vector 'empty' is indeed empty.\n");
 	}
-}
+	assert(empty.begin() == empty.end());
+}

tests/0026.container/0001.vector/capacity.cc

@@ -1,4 +1,5 @@
-#include <fast_io.h>
+#include <cassert>
+#include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
 using namespace fast_io::mnp;
@@ -10,18 +11,22 @@ int main()
 
 	auto cap = v.capacity();
 	println("Initial size: ", v.size(), ", capacity: ", cap);
+	assert(v.size() == 0);
+	assert(v.capacity() == 0);
 
-	print("\nDemonstrate the capacity's growth policy."
+	print("\nDemonstrate the capacity'\''s growth policy."
 		  "\nSize:  Capacity:  Ratio:\n");
 	while (sz-- > 0)
 	{
 		v.push_back(sz);
 		if (cap != v.capacity())
 		{
 			println(left(v.size(), 7), left(v.capacity(), 11), left(float(v.capacity()) / static_cast<float>(cap), 10));
+			assert(v.capacity() > cap);
 			cap = v.capacity();
 		}
 	}
 
 	println("\nFinal size: ", v.size(), ", capacity: ", v.capacity());
+	assert(v.size() == 100);
 }

tests/0026.container/0001.vector/clear.cc

@@ -1,4 +1,5 @@
-#include <string_view>
+#include <cassert>
+#include <string_view>
 #include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
@@ -13,6 +14,10 @@ int main()
 {
 	fast_io::vector<int> container{1, 2, 3};
 	print_info("Before clear: ", container);
+	assert(!container.empty());
+	assert(container.size() == 3);
 	container.clear();
 	print_info("After clear: ", container);
-}
+	assert(container.empty());
+	assert(container.size() == 0);
+}

tests/0026.container/0001.vector/data.cc

@@ -1,4 +1,5 @@
-#include <cstddef>
+#include <cassert>
+#include <cstddef>
 #include <span>
 #include <fast_io.h>
 #include <fast_io_dsal/vector.h>
@@ -29,4 +30,9 @@ int main()
 
 	// std::span (C++20) is a safer alternative to separated pointer/size.
 	span_func({container.data(), container.size()});
-}
+
+	assert(container.data()[0] == 1);
+	assert(container.data()[1] == 2);
+	assert(container.data()[2] == 3);
+	assert(container.data()[3] == 4);
+}

tests/0026.container/0001.vector/emplace.cc

@@ -1,4 +1,5 @@
-#include <algorithm>
+#include <cassert>
+#include <algorithm>
 #include <ranges>
 #include <string>
 #include <fast_io.h>
@@ -62,4 +63,8 @@ int main()
 	container.emplace(container.end(), std::move(three));
 
 	println("content:\n ", rgvw(container | std::views::transform([](auto const &a) { return a.s; }), " "));
+	assert(container.size() == 3);
+	assert(container[0].s == "one");
+	assert(container[1].s == "two");
+	assert(container[2].s == "three");
 }

tests/0026.container/0001.vector/emplace_index.cc

@@ -1,6 +1,4 @@
-#include <algorithm>
-#include <ranges>
-#include <string>
+#include <cassert>
 #include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
@@ -13,6 +11,13 @@ int main()
 	vec.emplace_index(0,6);
 	vec.emplace_index(0,8);
 	vec.erase_index(0);
+	// After push_back(4): [4]
+	// After emplace_index(0,6): [6,4]
+	// After emplace_index(0,8): [8,6,4]
+	// After erase_index(0): [6,4]
+	assert(vec.size() == 2);
+	assert(vec[0] == 6);
+	assert(vec[1] == 4);
 	for(auto const & e : vec)
 	{
 		::fast_io::io::println(e);

tests/0026.container/0001.vector/empty.cc

@@ -1,4 +1,5 @@
-#include <fast_io.h>
+#include <cassert>
+#include <fast_io.h>
 #include <fast_io_dsal/vector.h>
 using namespace fast_io::io;
 using namespace fast_io::mnp;
@@ -7,7 +8,9 @@ int main()
 {
 	fast_io::vector<int> numbers;
 	println("Initially, numbers.empty(): ", boolalpha(numbers.empty()));
+	assert(numbers.empty());
 
 	numbers.push_back(42);
 	println("After adding elements, numbers.empty(): ", boolalpha(numbers.empty()));
-}
+	assert(!numbers.empty());
+}