diff --git a/seismostats/analysis/tests/test_estimate_mc.py b/seismostats/analysis/tests/test_estimate_mc.py
index abd018c..2a47283 100644
--- a/seismostats/analysis/tests/test_estimate_mc.py
+++ b/seismostats/analysis/tests/test_estimate_mc.py
@@ -132,16 +132,21 @@ def test_empirical_cdf(setup_magnitudes, delta_m=0.1):
     # 1. with equal weights
     magnitudes = np.array([0.5, 0.6, 0.7, 0.8, 0.9])
     weights = np.array([1, 1, 1, 1, 1])
-    x, y = empirical_cdf(magnitudes, mc=0, delta_m=0.1, weights=weights)
-    assert_almost_equal(x, np.arange(0, 1, 0.1))
-    assert_almost_equal(y, [0, 0, 0, 0, 0, 0.2, 0.4, 0.6, 0.8, 1])
+    x_weight, y_weight = empirical_cdf(
+        magnitudes, mc=0, delta_m=0.1, weights=weights)
+    x, y = empirical_cdf(magnitudes, mc=0, delta_m=0.1)
+    assert_almost_equal(x_weight, np.arange(0, 1, 0.1))
+    assert_almost_equal(y_weight, [0, 0, 0, 0, 0, 0.2, 0.4, 0.6, 0.8, 1])
+    assert_almost_equal(x_weight, x)
+    assert_almost_equal(y_weight, y)
 
     # 2. with different weights
     magnitudes = np.array([0.5, 0.6, 0.7, 0.8, 0.9])
     weights = np.array([0.5, 0.5, 0.5, 0.5, 3])
-    x, y = empirical_cdf(magnitudes, mc=0, delta_m=0.1, weights=weights)
-    assert_almost_equal(x, np.arange(0, 1, 0.1))
-    assert_almost_equal(y, [0, 0, 0, 0, 0, 0.1, 0.2, 0.3, 0.4, 1])
+    x_weight, y_weight = empirical_cdf(
+        magnitudes, mc=0, delta_m=0.1, weights=weights)
+    assert_almost_equal(x_weight, np.arange(0, 1, 0.1))
+    assert_almost_equal(y_weight, [0, 0, 0, 0, 0, 0.1, 0.2, 0.3, 0.4, 1])
 
 
 @pytest.fixture