diff --git a/fit_discrete.py b/fit_discrete.py
index fc0c8cb..f764c0c 100644
--- a/fit_discrete.py
+++ b/fit_discrete.py
@@ -70,6 +70,11 @@ def set_plot(rows: int = 2, cols: int = 2):
     return axes.ravel()
 
 
+distributions = {'discrete uniform': stats.randint,
+                 'beta binomial': stats.betabinom,
+                 'zipfian': stats.zipf}
+
+
 if __name__ == '__main__':
     data = read_file('test_data.txt')
 
@@ -77,9 +82,6 @@ def set_plot(rows: int = 2, cols: int = 2):
 
     show_data(data, ax=axs[0], title='Input data')
 
-    distributions = {'discrete uniform': stats.randint,
-                     'beta binomial': stats.betabinom,
-                     'zipfian': stats.zipf}
     bounds = guess_bounds(data)
 
     for i, (key, dist) in enumerate(distributions.items()):
diff --git a/tests.py b/tests.py
new file mode 100644
index 0000000..1d999ea
--- /dev/null
+++ b/tests.py
@@ -0,0 +1,30 @@
+import pytest
+from scipy import stats
+from fit_discrete import read_file, distributions, fit_distribution, guess_bounds
+
+
+@pytest.mark.parametrize("key, expected", [('discrete uniform', 6.591673732008659),
+                                           ('beta binomial', 6.068425588244196),
+                                           ('zipfian', 7.86098064513523)])
+def test_results(key, expected):
+    data = read_file('test_data.txt')
+    bounds = guess_bounds(data)
+
+    res = fit_distribution(data, distributions[key], bounds[key])
+    assert res.success
+    assert pytest.approx(expected, res.nllf())
+
+
+def test_bounds():
+    data = stats.randint.rvs(low=0, high=10, size=100)
+    bounds = guess_bounds(data)
+
+    res = fit_distribution(data, stats.randint, bounds['discrete uniform'])
+    assert res.success
+
+    res = fit_distribution(data, stats.betabinom, bounds['beta binomial'])
+    assert res.success
+
+    res = fit_distribution(data, stats.zipf, bounds['zipfian'])
+    assert res.success
+