diff --git a/done.txt b/done.txt
index 344832ae21046d40f47702000ab8b31d0128114b..e1765211012274ecc357fd396c7df0309effc3a2 100644
--- a/done.txt
+++ b/done.txt
@@ -3,3 +3,4 @@ x 2015-12-23 decide on versioning system
 x 2015-12-24 move get_grid coords to interpolator                    @optimization +v1.0
 x 2015-12-25 get rid of temporal interpolation                       @optimization +v1.0
 x 2015-12-26 call interpolation only when needed                     @optimization +v1.0
+x 2015-12-26 clean up tox files, make sure all tests run             @tests        +v1.0
diff --git a/tests/test_interpolation.py b/tests/test_interpolation.py
index 928ae115370019c6b32a8720efddb77376d86a09..29755bd6a5207c322c7e442df89be28b7a996543 100644
--- a/tests/test_interpolation.py
+++ b/tests/test_interpolation.py
@@ -1,4 +1,3 @@
-#! /usr/bin/env python2
 #######################################################################
 #                                                                     #
 #  Copyright 2015 Max Planck Institute                                #
@@ -26,35 +25,44 @@
 
 
 import numpy as np
-from test_base import *
+from base import *
 import matplotlib.pyplot as plt
 
-class test_interpolation(bfps.NavierStokes):
-    def __init__(
-            self,
-            name = 'test_interpolation',
-            work_dir = './',
-            simname = 'test'):
-        super(test_interpolation, self).__init__(
-                work_dir = work_dir,
-                simname = simname,
-                name = name,
-                frozen_fields = True)
-        return None
-
 if __name__ == '__main__':
-    opt = parser.parse_args()
-    c = test_interpolation(work_dir = opt.work_dir + '/io')
+    opt = parser.parse_args(
+            ['-n', '32',
+             '--run',
+             '--ncpu', '2',
+             '--initialize',
+             '--neighbours', '4',
+             '--smoothness', '1',
+             '--nparticles', '4225',
+             '--niter_todo', '1',
+             '--niter_stat', '1',
+             '--niter_part', '1',
+             '--niter_out', '1',
+             '--wd', 'interp'] +
+            sys.argv[1:])
+    c = bfps.NavierStokes(
+            name = 'test_interpolation',
+            use_fftw_wisdom = False,
+            frozen_fields = True)
     c.pars_from_namespace(opt)
+    c.fill_up_fluid_code()
+    c.add_particle_fields(
+            name = 'n{0}m{1}'.format(opt.neighbours, opt.smoothness),
+            neighbours = opt.neighbours,
+            smoothness = opt.smoothness)
+    c.add_particle_fields(
+            name = 'n{0}'.format(opt.neighbours),
+            neighbours = opt.neighbours,
+            interp_type = 'Lagrange')
     c.add_particles(
             integration_steps = 1,
-            neighbours = 4,
-            smoothness = 1)
+            fields_name = 'n{0}m{1}'.format(opt.neighbours, opt.smoothness))
     c.add_particles(
             integration_steps = 1,
-            neighbours = 4,
-            interp_type = 'Lagrange')
-    c.fill_up_fluid_code()
+            fields_name = 'n{0}'.format(opt.neighbours))
     c.finalize_code()
     c.write_src()
     c.write_par()
diff --git a/todo.txt b/todo.txt
index 2356510f3170e2841465fa2231af6b11411fcd5b..a5a346cfa667d3a4192c733f4c786084ee9fa9a7 100644
--- a/todo.txt
+++ b/todo.txt
@@ -1,5 +1,4 @@
 (B) FFTW interpolator doesn't need its own field            @optimization +v1.0
-(B) clean up tox files, make sure all tests run             @tests        +v1.0
 (B) compute z polynomials only when needed                  @optimization +v1.0
 (B) use less memory                                         @optimization
 (B) split library into core and extra                       @optimization +v1.0
diff --git a/tox_interpolation.ini b/tox_interpolation.ini
deleted file mode 100644
index 71b94b2220f43496050b09855cf7e41b9e2da51e..0000000000000000000000000000000000000000
--- a/tox_interpolation.ini
+++ /dev/null
@@ -1,21 +0,0 @@
-[tox]
-envlist = py27
-[testenv]
-whitelist_externals =
-    echo
-    cp
-passenv = LD_LIBRARY_PATH
-changedir =
-    {envtmpdir}
-commands =
-    cp -r {toxinidir}/tests {envtmpdir}
-    python tests/test_interpolation.py \
-    -n 32 --ncpu 2 \
-    --initialize \
-    --nparticles 4225 \
-    --niter_todo 1 \
-    --niter_stat 1 \
-    --niter_part 1 \
-    --niter_out 1 \
-    --run
-