diff --git a/pyproject.toml b/pyproject.toml
index 7eeda50..dcb41ce 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@ documentation = "in construction"
 
 [project.optional-dependencies]
 ci = [
-    "pytest>=4.6",
+    "pytest",
     "coverage",
     "flake8",
 ]
diff --git a/tests/test_angles.py b/tests/test_angles.py
index 0843e1b..3c36380 100644
--- a/tests/test_angles.py
+++ b/tests/test_angles.py
@@ -1,6 +1,7 @@
 # %%
 import numpy as np
-from hyvr.objects.trough import trough
+from hyvr import trough
+from hyvr.tools import ferguson_curve
 
 
 # %%
@@ -33,3 +34,22 @@ def test_trough_angles():
 
     assert np.nanmax(dip) == 30.0
     assert np.nanmin(dip) >= 0.0
+
+
+def test_curve():
+    np.random.seed(37)
+    channel_curve_1 = ferguson_curve(
+        h=0.1,
+        k=np.pi / 200,
+        eps_factor=(np.pi / 1.5) ** 2,
+        flow_angle=0.0,
+        s_max=400,
+        xstart=40.0,
+        ystart=25.0,
+    )
+    curve = np.column_stack([channel_curve_1[0], channel_curve_1[1]])
+    assert curve[0, 0] == 40.0
+    assert curve[0, 1] == 25.0
+    s = channel_curve_1[4]
+    print(s)
+    assert s[-1] <= 400.0