test/non-swappable-ring-buffer: add test to confirm non-swappable containers can be used

test/non-swappable-ring-buffer.cpp

@@ -0,0 +1,77 @@
+#include <vector>
+#include <cassert>
+#include <ring-buffer.h>
+
+struct non_swappable_array {
+    using value_type = int;
+    using size_type = size_t;
+    int data[4];
+
+    // non-copyable
+    non_swappable_array() = default;
+    non_swappable_array(const non_swappable_array&) = delete;
+    non_swappable_array& operator=(const non_swappable_array&) = delete;
+
+    size_t size() const {
+        return 4;
+    }
+
+    int * begin() {
+        return std::begin(data);
+    }
+
+    int * end() {
+        return std::end(data);
+    }
+
+    const int * cbegin() const {
+        return std::cbegin(data);
+    }
+
+    const int * cend() const {
+        return std::cend(data);
+    }
+
+    int& operator[](size_t i) {
+        return data[i];
+    }
+
+    const int& operator[](size_t i) const {
+        return data[i];
+    }
+
+    // note: no swap implementation
+};
+
+int main() {
+    basic_ring_buffer<non_swappable_array> buf;
+
+    buf.push_back(1);
+    buf.push_back(2);
+    buf.push_back(3);
+    buf.push_back(4);
+    buf.push_back(5);
+    buf.push_back(6);
+
+    {
+        std::vector<int> expected{13, 14, 15, 16};
+        std::vector<int> actual;
+        for (int& i : buf) {
+            i += 10;
+            actual.push_back(i);
+        }
+        assert(actual == expected);
+    }
+
+    buf.push_back(7);
+
+    {
+        std::vector<int> expected{24, 25, 26, 17};
+        std::vector<int> actual;
+        for (int& i : buf) {
+            i += 10;
+            actual.push_back(i);
+        }
+        assert(actual == expected);
+    }
+}