test: add additional tests around swapping and iterators

test/swap-ring-buffer.cpp

@@ -0,0 +1,44 @@
+#include <vector>
+#include <cassert>
+#include <ring-buffer.h>
+#include <utility>
+
+int main() {
+    ring_buffer<int, 4> buf1;
+
+    buf1.push_back(1);
+    buf1.push_back(2);
+    buf1.push_back(3);
+    buf1.push_back(4);
+    buf1.push_back(5);
+    buf1.push_back(6);
+
+    ring_buffer<int, 4> buf2;
+
+    buf2.push_back(10);
+    buf2.push_back(20);
+    buf2.push_back(30);
+    buf2.push_back(40);
+    buf2.push_back(50);
+    buf2.push_back(60);
+
+    std::swap(buf1, buf2);
+
+    {
+        std::vector<int> expected{30, 40, 50, 60};
+        std::vector<int> actual;
+        for (int& i : buf1) {
+            actual.push_back(i);
+        }
+        assert(actual == expected);
+    }
+
+    {
+        std::vector<int> expected{3, 4, 5, 6};
+        std::vector<int> actual;
+        for (int& i : buf2) {
+            actual.push_back(i);
+        }
+        assert(actual == expected);
+    }
+}