diff --git a/ell1fit/ell1fit.py b/ell1fit/ell1fit.py
index f39b6a7..9c21481 100755
--- a/ell1fit/ell1fit.py
+++ b/ell1fit/ell1fit.py
@@ -997,7 +997,7 @@ def assign_logpriors(
 
 
 def order_of_magnitude(value):
-    return 10 ** np.int(np.log10(np.abs(value)) - 1)
+    return 10 ** int(np.log10(np.abs(value)) - 1)
 
 
 def get_factors(parnames, model, observation_length):
diff --git a/ell1fit/tests/data/events0.nc b/ell1fit/tests/data/events0.nc
new file mode 100755
index 0000000..c6bfc13
Binary files /dev/null and b/ell1fit/tests/data/events0.nc differ
diff --git a/ell1fit/tests/data/events0.par b/ell1fit/tests/data/events0.par
new file mode 100755
index 0000000..eec5a90
--- /dev/null
+++ b/ell1fit/tests/data/events0.par
@@ -0,0 +1,27 @@
+# Created: 2022-05-03T20:36:51.557233
+# PINT_version: 0.8.5
+# User: meo
+# Host: portabile3.home-life.hub
+# OS: macOS-10.16-x86_64-i386-64bit
+# Format: pint
+PSR                                 Dummy
+EPHEM                               DE421
+RAJ                      9:55:51.04010000
+DECJ                    69:40:45.49010000
+PMRA                                  0.0
+PMDEC                                 0.0
+F0                                    7.5 0.000000000001
+F1                                    0.0
+PEPOCH                              56357
+PLANET_SHAPIRO                          N
+BINARY                               ELL1
+PB                               2.532971 0.000001
+PBDOT                                   0
+A1                                 22.215 0.001
+TASC               56682.0669000000000000 0.00000001
+EPS1                                  0.0
+EPS2                                  0.0
+TZRMJD             56699.5093620635053249
+TZRSITE                               ssb
+TZRFRQ                                inf
+
diff --git a/ell1fit/tests/data/events1.nc b/ell1fit/tests/data/events1.nc
new file mode 100755
index 0000000..8cab228
Binary files /dev/null and b/ell1fit/tests/data/events1.nc differ
diff --git a/ell1fit/tests/data/events1.par b/ell1fit/tests/data/events1.par
new file mode 100755
index 0000000..eec5a90
--- /dev/null
+++ b/ell1fit/tests/data/events1.par
@@ -0,0 +1,27 @@
+# Created: 2022-05-03T20:36:51.557233
+# PINT_version: 0.8.5
+# User: meo
+# Host: portabile3.home-life.hub
+# OS: macOS-10.16-x86_64-i386-64bit
+# Format: pint
+PSR                                 Dummy
+EPHEM                               DE421
+RAJ                      9:55:51.04010000
+DECJ                    69:40:45.49010000
+PMRA                                  0.0
+PMDEC                                 0.0
+F0                                    7.5 0.000000000001
+F1                                    0.0
+PEPOCH                              56357
+PLANET_SHAPIRO                          N
+BINARY                               ELL1
+PB                               2.532971 0.000001
+PBDOT                                   0
+A1                                 22.215 0.001
+TASC               56682.0669000000000000 0.00000001
+EPS1                                  0.0
+EPS2                                  0.0
+TZRMJD             56699.5093620635053249
+TZRSITE                               ssb
+TZRFRQ                                inf
+
diff --git a/ell1fit/tests/test_execution.py b/ell1fit/tests/test_execution.py
new file mode 100644
index 0000000..271fb5c
--- /dev/null
+++ b/ell1fit/tests/test_execution.py
@@ -0,0 +1,42 @@
+import os
+import glob
+from ell1fit.ell1fit import main as main_ell1fit
+from ell1fit.create_parfile import main as main_ell1par
+
+
+curdir = os.path.abspath(os.path.dirname(__file__))
+datadir = os.path.join(curdir, "data")
+
+
+class TestExecution():
+    @classmethod
+    def setup_class(cls):
+        cls.event_files = sorted(glob.glob(os.path.join(datadir, "events[01].nc")))
+        cls.param_files = sorted(glob.glob(os.path.join(datadir, "events[01].par")))
+
+    def test_ell1fit_and_ell1par(self):
+        cmdlines = self.event_files + ["-p"] + self.param_files + ["-P", "F0,PB,A1,TASC"]
+
+        cmdline1 = cmdlines + ["--nsteps", "100"]
+        cmdline2 = cmdlines + ["--nsteps", "200"]
+
+        # Get to 100, then continue up to 200
+        main_ell1fit(cmdline1)
+        main_ell1fit(cmdline2)
+
+        outputs = sorted(glob.glob(os.path.join(datadir, "events[01]_A1_F0_PB_TASC_results.ecsv")))
+        for out in outputs:
+            assert os.path.exists(out)
+
+        main_ell1par(f"{outputs[0]} -p {self.param_files[0]}".split())
+        main_ell1par(f"{outputs[1]} -p {self.param_files[1]}".split())
+
+        out_param = sorted(glob.glob(os.path.join(datadir, "events[01]_A1_F0_PB_TASC_results.par")))
+        for out in out_param:
+            assert os.path.exists(out)
+
+    @classmethod
+    def teardown_class(cls):
+        outs = glob.glob(os.path.join(datadir, '*A1_*TASC*'))
+        for out in outs:
+            os.remove(out)
diff --git a/setup.cfg b/setup.cfg
index 14e5776..28525e2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -27,6 +27,9 @@ install_requires =
     stingray
     hendrics
     colorama
+    netcdf4
+    h5py
+    pyyaml
 
 
 [options.extras_require]
@@ -37,6 +40,7 @@ docs =
 
 [options.package_data]
 ell1fit = data/*
+ell1fit.tests = data/*
 
 [tool:pytest]
 testpaths = "ell1fit" "docs"