add condition on x and res are incompatible, update test.

src/diffpy/srmise/dataclusters.py

@@ -136,6 +136,9 @@ def setdata(self, x, y, res):
         self.x = x
         self.y = y
         self.res = res
+        # check x and res value are compatible.
+        if x.size == 0 and res != 0:
+            raise ValueError("It produces trivial clustering, please set 'res' to positive values.")
         # If x sequence size is empty, set the object into Initialized state.
         if x.size == 0 and res == 0:
             self.data_order = np.array([])

src/diffpy/srmise/tests/test_dataclusters.py

@@ -1,30 +1,12 @@
 import numpy as np
-import pytest
 
 from diffpy.srmise.dataclusters import DataClusters
 
 
-@pytest.mark.parametrize(
-    "inputs, expected",
-    [
-        (
-            {
-                "input_x": np.array([1, 2, 3]),
-                "input_y": np.array([3, 2, 1]),
-                "input_res": 4,
-            },
-            {
-                "x": np.array([]),
-                "y": np.array([]),
-                "res": 0,
-            },
-        ),
-    ],
-)
-def test_clear(inputs, expected):
+def test_clear():
     # Initialize DataClusters with input parameters
-    actual = DataClusters(x=inputs["input_x"], y=inputs["input_y"], res=inputs["input_res"])
-    expected = DataClusters(x=expected["x"], y=expected["y"], res=expected["res"])
+    actual = DataClusters(x=np.array([1, 2, 3]), y=np.array([3, 2, 1]), res=4)
+    expected = DataClusters(x=np.array([]), y=np.array([]), res=0)
     # Perform the clear operation
     actual.clear()
     assert actual == expected