diff --git a/src/csg/tests/meson.build b/src/csg/tests/meson.build
index 555396dc50c50f763c81cc5e9ef1706b78ef552e..82895dac4a19912bd27e566778ecf118edaddc1f 100644
--- a/src/csg/tests/meson.build
+++ b/src/csg/tests/meson.build
@@ -1,5 +1,5 @@
-unit_exe = executable(
-  'unit_tests',
+test_csg = executable(
+  'unit_tests_csg',
   'levelset/boolean.t.cpp',
   'levelset/primitives.t.cpp',
   'levelset/transform.t.cpp',
@@ -15,4 +15,4 @@ unit_exe = executable(
   link_with: lib_csg_parser,
   override_options: 'cpp_std=c++2a',
 )
-test('unit_test', unit_exe)
+test('unit_test_csg', test_csg)
diff --git a/src/inputs/geometry.cpp b/src/inputs/geometry.cpp
index 97cdc75ab69cf6a241403061b4242e7be02ab473..f21ae135363457a8ceac9a343a4cdd946237d5a7 100644
--- a/src/inputs/geometry.cpp
+++ b/src/inputs/geometry.cpp
@@ -1,9 +1,11 @@
+#include "solver.hpp"
 #include "solver_impl.hpp"
 
 namespace solver {
 
-solver::GeometrySettings make_geometry(solver::InputInfo ii,
-                                       std::vector<InputsMessage> &messages) {
+std::pair<solver::GeometrySettings, std::vector<InputsMessage>>
+make_geometry(solver::InputInfo ii) {
+  std::vector<InputsMessage> messages;
   solver::GeometrySettings geo;
 
   geo.csg_filename = "";
@@ -51,6 +53,6 @@ solver::GeometrySettings make_geometry(solver::InputInfo ii,
     std::get<1>(geo.axes).periodic = is_periodic[1];
     std::get<2>(geo.axes).periodic = is_periodic[2];
   }
-  return geo;
+  return std::make_pair(geo, messages);
 }
 } // namespace solver
diff --git a/src/inputs/mesh.cpp b/src/inputs/mesh.cpp
index d507fda1cec3ab3fce1f49f1a194833593757035..db021b85cb677e08c162c3af859fdcfbb5b95c24 100644
--- a/src/inputs/mesh.cpp
+++ b/src/inputs/mesh.cpp
@@ -1,9 +1,11 @@
+#include "solver.hpp"
 #include "solver_impl.hpp"
 
 namespace solver {
 
-solver::MeshSettings make_mesh(solver::InputInfo ii,
-                               std::vector<InputsMessage> &messages) {
+std::pair<solver::MeshSettings, std::vector<InputsMessage>>
+make_mesh(solver::InputInfo ii) {
+  std::vector<InputsMessage> messages;
   solver::MeshSettings mesh;
   auto [mx, my, mz] = mesh.axes;
 
@@ -99,6 +101,6 @@ solver::MeshSettings make_mesh(solver::InputInfo ii,
   mesh.axes[1] = my;
   mesh.axes[2] = mz;
 
-  return mesh;
+  return std::make_pair(mesh, messages);
 }
 } // namespace solver
diff --git a/src/inputs/solver.cpp b/src/inputs/solver.cpp
index c80a919ecd7b18b0d26938e7f9fffb910794d1a4..8576946d5b158b60f4e9f42d5ec29db1f29cbaa5 100644
--- a/src/inputs/solver.cpp
+++ b/src/inputs/solver.cpp
@@ -51,11 +51,20 @@ void add_msg(std::string key, std::vector<InputsMessage> &messages,
 
 std::pair<solver::SolverSettings, std::vector<InputsMessage>>
 make_solver(solver::InputInfo ii) {
-  std::vector<InputsMessage> messages;
   solver::SolverSettings ss;
-  ss.geometry = make_geometry(ii, messages);
-  ss.mesh = make_mesh(ii, messages);
-  ss.time = make_time(ii, messages);
+  auto [geometry, msgs] = make_geometry(ii);
+  auto [mesh, msgs2] = make_mesh(ii);
+  auto [time, msgs3] = make_time(ii);
+  ss.geometry = geometry;
+  ss.mesh = mesh;
+  ss.time = time;
+  std::vector<InputsMessage> messages;
+  for (auto msgz :
+       std::vector<std::vector<InputsMessage>>{msgs, msgs2, msgs3}) {
+    for (auto msg : msgz) {
+      messages.push_back(msg);
+    }
+  }
   return std::make_pair(ss, messages);
 }
 
diff --git a/src/inputs/solver_impl.hpp b/src/inputs/solver_impl.hpp
index b7e0c0ab9a13ceeedd8521b151ad2a0929c0ccc9..f854566dceeff31908c8afbd86552437f742db79 100644
--- a/src/inputs/solver_impl.hpp
+++ b/src/inputs/solver_impl.hpp
@@ -1,9 +1,12 @@
 #include <solver.hpp>
 
 namespace solver {
-GeometrySettings make_geometry(solver::InputInfo, std::vector<InputsMessage> &);
-MeshSettings make_mesh(solver::InputInfo, std::vector<InputsMessage> &);
-TimeSettings make_time(solver::InputInfo, std::vector<InputsMessage> &);
+std::pair<solver::GeometrySettings, std::vector<InputsMessage>>
+    make_geometry(solver::InputInfo);
+std::pair<solver::MeshSettings, std::vector<InputsMessage>>
+    make_mesh(solver::InputInfo);
+std::pair<solver::TimeSettings, std::vector<InputsMessage>>
+    make_time(solver::InputInfo);
 void add_missing_msg(std::string key, std::vector<InputsMessage> &, Array);
 void add_msg(std::string key, std::vector<InputsMessage> &, Array);
 } // namespace solver
diff --git a/src/inputs/tests/meson.build b/src/inputs/tests/meson.build
index 74f0aa91a640b4e78f172f2575977308cf691c48..2a9d2a85ad9dfefba7ec13db11fd8b8b5d6a26e5 100644
--- a/src/inputs/tests/meson.build
+++ b/src/inputs/tests/meson.build
@@ -1,9 +1,9 @@
-unit_exe = executable(
-  'unit_tests',
+test_inputs = executable(
+  'unit_tests_inputs',
   'parser.t.cpp',
   'solver.t.cpp',
   'main.cpp',
   include_directories: [parser_inc, catch2_inc],
   link_with: lib_inputs_parser
 )
-test('unit_test', unit_exe)
+test('unit_test_inputs', test_inputs)
diff --git a/src/inputs/tests/solver.t.cpp b/src/inputs/tests/solver.t.cpp
index e0ed6f74fee04ad5edaf28d60dd9e6b234289cab..c7343f4fb9073b39da0237c36fc31775460c804c 100644
--- a/src/inputs/tests/solver.t.cpp
+++ b/src/inputs/tests/solver.t.cpp
@@ -1,18 +1,35 @@
-// tests
-
 #include "catch2/catch.hpp"
 
 #include <inputs.hpp>
-#include <solver.hpp>
+#include <solver_impl.hpp>
 
-TEST_CASE("from_origin", "[]") {
+TEST_CASE("GeometrySettings", "[]") {
   solver::InputInfo ii;
 
-  // Geometry
   ii[PROB_LO] = std::vector<double>({-4, -5, -6});
   ii[PROB_HI] = solver::NumberArray({0.004, 0.001, 0.001});
-  ii[PERIODIC] = solver::NumberArray({0, 0, 0});
-  ii[CSG_FILENAME] = solver::StringArray({"geometry.csg",});
+  ii[PERIODIC] = solver::NumberArray({1, 0, 0});
+  ii[CSG_FILENAME] = solver::StringArray({
+      "geometry.csg",
+  });
+
+  auto [geo, messages] = solver::make_geometry(ii);
+
+  auto [xx, yy, zz] = geo.axes;
+  CHECK(xx.high == 0.004);
+  CHECK(xx.low == -4);
+  CHECK(yy.high == 0.001);
+  CHECK(yy.low == -5);
+  CHECK(zz.high == 0.001);
+  CHECK(zz.low == -6);
+  CHECK(xx.periodic);
+  CHECK_FALSE(yy.periodic);
+  CHECK_FALSE(zz.periodic);
+  CHECK(geo.csg_filename == "geometry.csg");
+}
+
+TEST_CASE("MeshSettings", "[]") {
+  solver::InputInfo ii;
 
   // Mesh
   ii[N_CELL] = solver::NumberArray({11, 22, 33});
@@ -27,32 +44,11 @@ TEST_CASE("from_origin", "[]") {
   ii[PARTICLE_GRID_SIZE_Y] = solver::NumberArray({95});
   ii[PARTICLE_GRID_SIZE_Z] = solver::NumberArray({96});
 
-  // Time
-  ii[DT_MAX] = solver::NumberArray({99.99});
-  ii[DT_MIN] = solver::NumberArray({0.001});
-  ii[MAXSTEP] = solver::NumberArray({39});
-  ii[TSTOP] = solver::NumberArray({3.14});
-  ii[FIXED_DT] = solver::NumberArray({1});
-  ii[CFL] = solver::NumberArray({0.77});
-  ii[TCOLL_RATIO] = solver::NumberArray({49.2});
+  auto [mesh, messages] = solver::make_mesh(ii);
 
-  auto [sv, messages] = solver::make_solver(ii);
-
-  SECTION(" Geometry fields ") {
-    auto [xx, yy, zz] = sv.geometry.axes;
-    CHECK(xx.high == 0.004);
-    CHECK(xx.low == -4);
-    CHECK(yy.high == 0.001);
-    CHECK(yy.low == -5);
-    CHECK(zz.high == 0.001);
-    CHECK(zz.low == -6);
-    CHECK_FALSE(xx.periodic);
-    CHECK_FALSE(yy.periodic);
-    CHECK_FALSE(zz.periodic);
-  }
   SECTION(" Mesh fields ") {
-    CHECK(sv.mesh.blocking_factor == 222);
-    auto [mx, my, mz] = sv.mesh.axes;
+    CHECK(mesh.blocking_factor == 222);
+    auto [mx, my, mz] = mesh.axes;
     CHECK(mx.n_cell == 11);
     CHECK(my.n_cell == 22);
     CHECK(mz.n_cell == 33);
@@ -69,15 +65,30 @@ TEST_CASE("from_origin", "[]") {
     CHECK(my.fluid_max_tile_size == 4567);
     CHECK(mz.fluid_max_tile_size == 7890);
   }
+}
+
+TEST_CASE("TimeSettings", "[]") {
+  solver::InputInfo ii;
+
+  // Time
+  ii[DT_MAX] = solver::NumberArray({99.99});
+  ii[DT_MIN] = solver::NumberArray({0.001});
+  ii[MAXSTEP] = solver::NumberArray({39});
+  ii[TSTOP] = solver::NumberArray({3.14});
+  ii[FIXED_DT] = solver::NumberArray({1});
+  ii[CFL] = solver::NumberArray({0.77});
+  ii[TCOLL_RATIO] = solver::NumberArray({49.2});
+
+  auto [time, messages] = solver::make_time(ii);
 
   SECTION(" Time fields ") {
-    CHECK(sv.time.dt_max == 99.99);
-    CHECK(sv.time.dt_min == 0.001);
-    CHECK(sv.time.max_step == 39);
-    CHECK(sv.time.tstop == 3.14);
-    CHECK(sv.time.fixed_dt);
-    CHECK(sv.time.cfl == 0.77);
-    CHECK(sv.time.tcoll_ratio == 49.2);
+    CHECK(time.dt_max == 99.99);
+    CHECK(time.dt_min == 0.001);
+    CHECK(time.max_step == 39);
+    CHECK(time.tstop == 3.14);
+    CHECK(time.fixed_dt);
+    CHECK(time.cfl == 0.77);
+    CHECK(time.tcoll_ratio == 49.2);
   }
 }
 
diff --git a/src/inputs/time.cpp b/src/inputs/time.cpp
index 3748610be5a3e488bb1c6c2cdac0c17cabcbde2e..000dda197e02b54954841320fb1f9587a0fa23ed 100644
--- a/src/inputs/time.cpp
+++ b/src/inputs/time.cpp
@@ -2,8 +2,9 @@
 
 namespace solver {
 
-solver::TimeSettings make_time(solver::InputInfo ii,
-                               std::vector<InputsMessage> &messages) {
+std::pair<solver::TimeSettings, std::vector<InputsMessage>>
+make_time(solver::InputInfo ii) {
+  std::vector<InputsMessage> messages;
   solver::TimeSettings time;
 
   auto dt_max = std::get<solver::NumberArray>(ii[DT_MAX]);
@@ -58,6 +59,6 @@ solver::TimeSettings make_time(solver::InputInfo ii,
     time.tcoll_ratio = tcoll_ratio[0];
   }
 
-  return time;
+  return std::make_pair(time, messages);
 }
 } // namespace solver