diff --git a/qtensor/compression/compressed_contraction.py b/qtensor/compression/compressed_contraction.py
index 893987f9..1023021c 100644
--- a/qtensor/compression/compressed_contraction.py
+++ b/qtensor/compression/compressed_contraction.py
@@ -203,5 +203,5 @@ def compressed_sum(A:Tensor, sum_ixs,
             R = Tensor(new_tensor_name, result_indices, data=chunk)
         else:
             R.set_chunk(r_i, chunk)
-        compressor.compressor.free_decompressed()
+        compressor.free_decompressed()
     return R
diff --git a/qtensor/compression/tests/test_compressed_energy_expectation.py b/qtensor/compression/tests/test_compressed_energy_expectation.py
new file mode 100644
index 00000000..895999f9
--- /dev/null
+++ b/qtensor/compression/tests/test_compressed_energy_expectation.py
@@ -0,0 +1,24 @@
+import qtensor
+import numpy as np
+from qtensor.compression import CUSZPCompressor
+import qtensor.tests
+
+def test_compress_energy_expect():
+    G, gamma, beta = qtensor.tests.get_test_problem(n=10, p=2, type='random')
+    edge = list(G.edges())[0]
+    composer = qtensor.QtreeQAOAComposer(G, gamma=gamma, beta=beta)
+    composer.energy_expectation_lightcone(edge)
+    circuit = composer.circuit
+    base_backend = qtensor.contraction_backends.get_backend('cupy')
+    compressor = CUSZPCompressor(r2r_error=1e-4, r2r_threshold=1e-4)
+    backend = qtensor.contraction_backends.CompressionBackend(base_backend, compressor, max_tw=6)
+    sim = qtensor.QtreeSimulator(backend=backend)
+    res = sim.simulate(circuit)
+    sim_exact = qtensor.QtreeSimulator(backend=base_backend)
+    ref = sim_exact.simulate(circuit)
+    print(f'exact: {ref}, compressed: {res}')
+    assert np.allclose(res, ref, atol=1e-4, rtol=0.05)
+
+if __name__ == '__main__':
+    test_energy_expect()
+    print('test passed!')