add more tests

test/push-iterate-constexpr.cpp

@@ -0,0 +1,52 @@
+#include <array>
+#include <ring-buffer.h>
+
+template <typename T, size_t N>
+constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b) {
+    for (size_t i = 0; i < N; i++) {
+        if (a[i] != b[i]) return false;
+    }
+
+    return true;
+}
+
+constexpr bool test() {
+    ring_buffer<int, 4> 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::array<int, 4> expected{13, 14, 15, 16};
+        std::array<int, 4> actual;
+        int actual_index = 0;
+        for (int& i : buf) {
+            i += 10;
+            actual[actual_index++] = i;
+        }
+        if (!array_equal(actual, expected)) return false;
+    }
+
+    buf.push_back(7);
+
+    {
+        std::array<int, 4> expected{24, 25, 26, 17};
+        std::array<int, 4> actual;
+        int actual_index = 0;
+        for (int& i : buf) {
+            i += 10;
+            actual[actual_index++] = i;
+        }
+        if (!array_equal(actual, expected)) return false;
+    }
+
+    return true;
+}
+
+static_assert(test());
+
+int main() {}