feat(preconditioner): major work on preconditioner system

first preconditioner MVP

tests/mpi/mpi_test_main.cpp

@@ -0,0 +1,58 @@
+#include <catch2/catch_session.hpp>
+#include <cstdint>
+#include <iostream>
+#include <mfem.hpp>
+#include <string>
+#include <vector>
+
+int main(
+    int argc,
+    char *argv[]
+) {
+    mfem::Mpi::Init(argc, argv);
+
+    const int rank = mfem::Mpi::WorldRank();
+    std::vector<std::string> arguments;
+    arguments.reserve(static_cast<std::size_t>(argc) + 6);
+    for (int index = 0; index < argc; ++index) {
+        arguments.emplace_back(argv[index]);
+    }
+
+    arguments.emplace_back("--order");
+    arguments.emplace_back("lex");
+    arguments.emplace_back("--rng-seed");
+    arguments.emplace_back("184467");
+
+    if (rank != 0) {
+        arguments.emplace_back("--out");
+        arguments.emplace_back("/dev/null");
+    }
+
+    std::vector<const char *> catch_arguments;
+    catch_arguments.reserve(arguments.size());
+    for (const std::string &argument : arguments) {
+        catch_arguments.push_back(argument.c_str());
+    }
+
+    int local_result = 0;
+    {
+        Catch::Session session;
+        if (const int parse_result =
+                session.applyCommandLine(static_cast<int>(catch_arguments.size()), catch_arguments.data());
+            parse_result != 0) {
+            local_result = parse_result;
+        } else {
+            local_result = session.run();
+        }
+    }
+
+    int global_result = 0;
+    MPI_Allreduce(&local_result, &global_result, 1, MPI_INT, MPI_MAX, MPI_COMM_WORLD);
+
+    if (rank == 0 && global_result != 0 && local_result == 0) {
+        std::cerr << "At least one non-root MPI rank reported a test failure.\n";
+    }
+
+    mfem::Mpi::Finalize();
+    return global_result;
+}