diff --git a/test/sampler_test.py b/test/sampler_test.py
index a2b76a4ab3b030fc00085fe5282710d161ab20d0..7ee7c4b00d2c56291fbc9f2d0dd83f1356a9022c 100644
--- a/test/sampler_test.py
+++ b/test/sampler_test.py
@@ -441,7 +441,7 @@ class TestRunningSamplers(unittest.TestCase):
     def test_run_PTMCMCSampler(self):
         _ = bilby.run_sampler(
             likelihood=self.likelihood, priors=self.priors,
-            sampler= 'PTMCMCsampler'', Niter=100, save=False)
+            sampler= 'PTMCMCsampler', Niter=100, save=False)
 
 
 if __name__ == '__main__':