TEST: fix dummy likelihood

test/core/sampler/dynesty_test.py

 import unittest
 from copy import deepcopy
-from unittest.mock import MagicMock
 
 from attr import define
 import bilby
@@ -22,9 +21,22 @@ class Dummy:
     loglstar: float = -1
 
 
+class DummyLikelihood(bilby.core.likelihood.Likelihood):
+    """
+    A trivial likelihood used for testing. Add some randomness so the likelihood
+    isn't flat everywhere as that can cause issues for nested samplers.
+    """
+
+    def __init__(self):
+        super().__init__(dict())
+
+    def log_likelihood(self):
+        return np.random.uniform(0, 0.01)
+
+
 class TestDynesty(unittest.TestCase):
     def setUp(self):
-        self.likelihood = MagicMock()
+        self.likelihood = DummyLikelihood()
         self.priors = bilby.core.prior.PriorDict(
             dict(a=bilby.core.prior.Uniform(0, 1), b=bilby.core.prior.Uniform(0, 1))
         )