diff --git a/tests/utilities/basic_routines.py b/tests/1_utilities/basic_routines.py
similarity index 100%
rename from tests/utilities/basic_routines.py
rename to tests/1_utilities/basic_routines.py
diff --git a/tests/utilities/fenics_const.py b/tests/1_utilities/fenics_const.py
similarity index 100%
rename from tests/utilities/fenics_const.py
rename to tests/1_utilities/fenics_const.py
diff --git a/tests/utilities/fenics_norms.py b/tests/1_utilities/fenics_norms.py
similarity index 100%
rename from tests/utilities/fenics_norms.py
rename to tests/1_utilities/fenics_norms.py
diff --git a/tests/utilities/heaviside_fitting.py b/tests/1_utilities/heaviside_fitting.py
similarity index 100%
rename from tests/utilities/heaviside_fitting.py
rename to tests/1_utilities/heaviside_fitting.py
diff --git a/tests/utilities/nearest_neighbor_fitting.py b/tests/1_utilities/nearest_neighbor_fitting.py
similarity index 100%
rename from tests/utilities/nearest_neighbor_fitting.py
rename to tests/1_utilities/nearest_neighbor_fitting.py
diff --git a/tests/utilities/parameter_sampling.py b/tests/1_utilities/parameter_sampling.py
similarity index 100%
rename from tests/utilities/parameter_sampling.py
rename to tests/1_utilities/parameter_sampling.py
diff --git a/tests/utilities/poly_fitting.py b/tests/1_utilities/poly_fitting.py
similarity index 100%
rename from tests/utilities/poly_fitting.py
rename to tests/1_utilities/poly_fitting.py
diff --git a/tests/utilities/radial_fitting.py b/tests/1_utilities/radial_fitting.py
similarity index 100%
rename from tests/utilities/radial_fitting.py
rename to tests/1_utilities/radial_fitting.py
diff --git a/tests/utilities/sampling.py b/tests/1_utilities/sampling.py
similarity index 100%
rename from tests/utilities/sampling.py
rename to tests/1_utilities/sampling.py
diff --git a/tests/hfengines/fracture.py b/tests/2_hfengines/fracture.py
similarity index 100%
rename from tests/hfengines/fracture.py
rename to tests/2_hfengines/fracture.py
diff --git a/tests/hfengines/helmholtz_box_scattering_problem_engine.py b/tests/2_hfengines/helmholtz_box_scattering_problem_engine.py
similarity index 100%
rename from tests/hfengines/helmholtz_box_scattering_problem_engine.py
rename to tests/2_hfengines/helmholtz_box_scattering_problem_engine.py
diff --git a/tests/hfengines/helmholtz_cavity_scattering_problem_engine.py b/tests/2_hfengines/helmholtz_cavity_scattering_problem_engine.py
similarity index 100%
rename from tests/hfengines/helmholtz_cavity_scattering_problem_engine.py
rename to tests/2_hfengines/helmholtz_cavity_scattering_problem_engine.py
diff --git a/tests/hfengines/helmholtz_elasticity.py b/tests/2_hfengines/helmholtz_elasticity.py
similarity index 100%
rename from tests/hfengines/helmholtz_elasticity.py
rename to tests/2_hfengines/helmholtz_elasticity.py
diff --git a/tests/hfengines/helmholtz_external.py b/tests/2_hfengines/helmholtz_external.py
similarity index 100%
rename from tests/hfengines/helmholtz_external.py
rename to tests/2_hfengines/helmholtz_external.py
diff --git a/tests/hfengines/helmholtz_internal.py b/tests/2_hfengines/helmholtz_internal.py
similarity index 100%
rename from tests/hfengines/helmholtz_internal.py
rename to tests/2_hfengines/helmholtz_internal.py
diff --git a/tests/hfengines/helmholtz_square_bubble_domain_problem_engine.py b/tests/2_hfengines/helmholtz_square_bubble_domain_problem_engine.py
similarity index 100%
rename from tests/hfengines/helmholtz_square_bubble_domain_problem_engine.py
rename to tests/2_hfengines/helmholtz_square_bubble_domain_problem_engine.py
diff --git a/tests/hfengines/helmholtz_square_bubble_problem_engine.py b/tests/2_hfengines/helmholtz_square_bubble_problem_engine.py
similarity index 100%
rename from tests/hfengines/helmholtz_square_bubble_problem_engine.py
rename to tests/2_hfengines/helmholtz_square_bubble_problem_engine.py
diff --git a/tests/hfengines/helmholtz_square_transmission_problem_engine.py b/tests/2_hfengines/helmholtz_square_transmission_problem_engine.py
similarity index 100%
rename from tests/hfengines/helmholtz_square_transmission_problem_engine.py
rename to tests/2_hfengines/helmholtz_square_transmission_problem_engine.py
diff --git a/tests/hfengines/laplace.py b/tests/2_hfengines/laplace.py
similarity index 100%
rename from tests/hfengines/laplace.py
rename to tests/2_hfengines/laplace.py
diff --git a/tests/hfengines/laplace_disk_gaussian.py b/tests/2_hfengines/laplace_disk_gaussian.py
similarity index 100%
rename from tests/hfengines/laplace_disk_gaussian.py
rename to tests/2_hfengines/laplace_disk_gaussian.py
diff --git a/tests/hfengines/linear_elasticity.py b/tests/2_hfengines/linear_elasticity.py
similarity index 100%
rename from tests/hfengines/linear_elasticity.py
rename to tests/2_hfengines/linear_elasticity.py
diff --git a/tests/hfengines/linear_elasticity_beam_poisson_ratio_engine.py b/tests/2_hfengines/linear_elasticity_beam_poisson_ratio_engine.py
similarity index 100%
rename from tests/hfengines/linear_elasticity_beam_poisson_ratio_engine.py
rename to tests/2_hfengines/linear_elasticity_beam_poisson_ratio_engine.py
diff --git a/tests/hfengines/matrix.py b/tests/2_hfengines/matrix.py
similarity index 100%
rename from tests/hfengines/matrix.py
rename to tests/2_hfengines/matrix.py
diff --git a/tests/hfengines/membrane_fracture_engine.py b/tests/2_hfengines/membrane_fracture_engine.py
similarity index 100%
rename from tests/hfengines/membrane_fracture_engine.py
rename to tests/2_hfengines/membrane_fracture_engine.py
diff --git a/tests/hfengines/membrane_fracture_nodomain_engine.py b/tests/2_hfengines/membrane_fracture_nodomain_engine.py
similarity index 100%
rename from tests/hfengines/membrane_fracture_nodomain_engine.py
rename to tests/2_hfengines/membrane_fracture_nodomain_engine.py
diff --git a/tests/hfengines/rod.xml b/tests/2_hfengines/rod.xml
similarity index 100%
rename from tests/hfengines/rod.xml
rename to tests/2_hfengines/rod.xml
diff --git a/tests/hfengines/rod_3d.py b/tests/2_hfengines/rod_3d.py
similarity index 96%
rename from tests/hfengines/rod_3d.py
rename to tests/2_hfengines/rod_3d.py
index 528e0f1..e5da838 100644
--- a/tests/hfengines/rod_3d.py
+++ b/tests/2_hfengines/rod_3d.py
@@ -1,37 +1,37 @@
 # Copyright (C) 2018 by the RROMPy authors
 #
 # This file is part of RROMPy.
 #
 # RROMPy is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Lesser General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # RROMPy is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public License
 # along with RROMPy. If not, see <http://www.gnu.org/licenses/>.
 #
 
 import fenics as fen
 from rrompy.hfengines.vector_linear_problem import (
                                                  LinearElasticityProblemEngine)
 
 def rod3Dsolver():
-    mesh = fen.Mesh("./tests/hfengines/rod.xml")
+    mesh = fen.Mesh("./tests/2_hfengines/rod.xml")
     rho_ = 1e3
     nu = .45
     E = 1e6
     g = 1e3
     solver = LinearElasticityProblemEngine(verbosity = 0)
     solver.V = fen.VectorFunctionSpace(mesh, "P", 1)
     solver.lambda_ = E * nu / (1. + nu) / (1. - 2 * nu)
     solver.mu_ = E / (1. + nu)
     solver.forcingTerm = [fen.Constant((0., - rho_ * g / E, 0.)),
                           fen.Constant((0., 0., 0.))]
     solver.DirichletBoundary = lambda x, on_b: on_b and fen.near(x[2], 0.)
     solver.NeumannBoundary = "REST"
     return solver
diff --git a/tests/reduction_methods_1D/matrix_fft.py b/tests/3_reduction_methods_1D/matrix_fft.py
similarity index 100%
rename from tests/reduction_methods_1D/matrix_fft.py
rename to tests/3_reduction_methods_1D/matrix_fft.py
diff --git a/tests/reduction_methods_1D/rational_interpolant_1d.py b/tests/3_reduction_methods_1D/rational_interpolant_1d.py
similarity index 100%
rename from tests/reduction_methods_1D/rational_interpolant_1d.py
rename to tests/3_reduction_methods_1D/rational_interpolant_1d.py
diff --git a/tests/reduction_methods_1D/rational_interpolant_greedy_1d.py b/tests/3_reduction_methods_1D/rational_interpolant_greedy_1d.py
similarity index 100%
rename from tests/reduction_methods_1D/rational_interpolant_greedy_1d.py
rename to tests/3_reduction_methods_1D/rational_interpolant_greedy_1d.py
diff --git a/tests/reduction_methods_1D/reduced_basis_1d.py b/tests/3_reduction_methods_1D/reduced_basis_1d.py
similarity index 100%
rename from tests/reduction_methods_1D/reduced_basis_1d.py
rename to tests/3_reduction_methods_1D/reduced_basis_1d.py
diff --git a/tests/reduction_methods_1D/reduced_basis_greedy_1d.py b/tests/3_reduction_methods_1D/reduced_basis_greedy_1d.py
similarity index 100%
rename from tests/reduction_methods_1D/reduced_basis_greedy_1d.py
rename to tests/3_reduction_methods_1D/reduced_basis_greedy_1d.py
diff --git a/tests/reduction_methods_multiD/greedy_pivoted_rational_2d.py b/tests/4_reduction_methods_multiD/greedy_pivoted_rational_2d.py
similarity index 100%
rename from tests/reduction_methods_multiD/greedy_pivoted_rational_2d.py
rename to tests/4_reduction_methods_multiD/greedy_pivoted_rational_2d.py
diff --git a/tests/reduction_methods_multiD/matrix_random.py b/tests/4_reduction_methods_multiD/matrix_random.py
similarity index 100%
rename from tests/reduction_methods_multiD/matrix_random.py
rename to tests/4_reduction_methods_multiD/matrix_random.py
diff --git a/tests/reduction_methods_multiD/pivoted_rational_2d.py b/tests/4_reduction_methods_multiD/pivoted_rational_2d.py
similarity index 100%
rename from tests/reduction_methods_multiD/pivoted_rational_2d.py
rename to tests/4_reduction_methods_multiD/pivoted_rational_2d.py
diff --git a/tests/reduction_methods_multiD/rational_interpolant_2d.py b/tests/4_reduction_methods_multiD/rational_interpolant_2d.py
similarity index 100%
rename from tests/reduction_methods_multiD/rational_interpolant_2d.py
rename to tests/4_reduction_methods_multiD/rational_interpolant_2d.py
diff --git a/tests/reduction_methods_multiD/reduced_basis_2d.py b/tests/4_reduction_methods_multiD/reduced_basis_2d.py
similarity index 100%
rename from tests/reduction_methods_multiD/reduced_basis_2d.py
rename to tests/4_reduction_methods_multiD/reduced_basis_2d.py