Add missing test.

src/test/func/memory_usage/memory_usage.cpp

@@ -0,0 +1,92 @@
+/**
+ * Memory usage test
+ * Query memory usage repeatedly
+ */
+
+#include <iostream>
+#include <test/setup.h>
+
+#define SNMALLOC_NAME_MANGLE(a) our_##a
+#include "../../../override/malloc.cc"
+
+using namespace snmalloc;
+
+bool
+print_memory_usage()
+{
+  static std::pair<size_t,size_t> last_memory_usage {0,0};
+
+  auto next_memory_usage = default_memory_provider().memory_usage();
+  if (next_memory_usage != last_memory_usage)
+  {
+    std::cout << "Memory Usages Changed to (" << next_memory_usage.first << ", " << next_memory_usage.second << ")" << std::endl;
+    last_memory_usage = next_memory_usage;
+    return true;
+  }
+  return false;
+}
+
+std::vector<void*> allocs;
+
+/**
+ * Add allocs until the statistics have changed n times.
+ */
+void add_n_allocs(size_t n)
+{
+  while (true)
+  {
+    allocs.push_back(our_malloc(1024));
+    if (print_memory_usage())
+    {
+      n--;
+      if (n == 0) break;
+    }
+  }
+}
+
+/**
+ * Remove allocs until the statistics have changed n times.
+ */
+void remove_n_allocs(size_t n)
+{
+  while (true)
+  {
+    our_free(allocs.back());
+    allocs.pop_back();
+    if (print_memory_usage())
+    {
+      n--;
+      if (n == 0) break;
+    }
+  }
+}
+
+int main(int argc, char** argv)
+{
+  UNUSED(argc);
+  UNUSED(argv);
+
+  setup();
+
+  add_n_allocs(5);
+  std::cout << "Init complete!" << std::endl;
+
+  for (int i = 0; i < 10; i++)
+  {
+    remove_n_allocs(1);
+    std::cout << "Phase " << i << " remove complete!" << std::endl;
+    add_n_allocs(2);
+    std::cout << "Phase " << i << " add complete!" << std::endl;
+  }
+
+  for (int i = 0; i < 10; i++)
+  {
+    remove_n_allocs(2);
+    std::cout << "Phase " << i << " remove complete!" << std::endl;
+    add_n_allocs(1);
+    std::cout << "Phase " << i << " add complete!" << std::endl;
+  }
+
+  remove_n_allocs(3);
+  std::cout << "Teardown complete!" << std::endl;
+}