diff --git a/tests/test_db_interface.py b/tests/test_db_interface.py
index c2ed6eb..2764d06 100755
--- a/tests/test_db_interface.py
+++ b/tests/test_db_interface.py
@@ -115,6 +115,16 @@ class TestDBInterface(unittest.TestCase):
             for _, e in entries.items():
                 self.assertIsNotNone(e['throughput'])
                 self.assertIsNotNone(e['latency'])
+            # remove empty line => no import since broken format
+            del input_data[3]
+            entries = dbi._get_asmbench_output(input_data, 'aarch64')
+            self.assertEqual(len(entries), 0)
+        with self.assertRaises(ValueError):
+            dbi.import_benchmark_output(
+                'csx', 'invalid_bench_type', self._find_file('asmbench_import_x86.dat')
+            )
+        with self.assertRaises(AssertionError):
+            dbi.import_benchmark_output('csx', 'ibench', 'invalid_file')
 
     ##################
     # Helper functions
diff --git a/tests/test_semantics.py b/tests/test_semantics.py
index eb3b13a..a702979 100755
--- a/tests/test_semantics.py
+++ b/tests/test_semantics.py
@@ -5,6 +5,7 @@ Unit tests for Semantic Analysis
 
 import os
 import unittest
+from copy import deepcopy
 from subprocess import call
 
 import networkx as nx
@@ -106,6 +107,26 @@ class TestSemanticTools(unittest.TestCase):
                 self.assertIsInstance(instruction_form['port_pressure'], list)
                 self.assertEqual(len(instruction_form['port_pressure']), port_num)
 
+    def test_optimal_throughput_assignment(self):
+        # x86
+        kernel_fixed = deepcopy(self.kernel_x86)
+        self.semantics_csx.add_semantics(kernel_fixed)
+        kernel_optimal = deepcopy(kernel_fixed)
+        self.semantics_csx.assign_optimal_throughput(kernel_optimal)
+        tp_fixed = self.semantics_csx.get_throughput_sum(kernel_fixed)
+        tp_optimal = self.semantics_csx.get_throughput_sum(kernel_optimal)
+        self.assertNotEqual(tp_fixed, tp_optimal)
+        self.assertTrue(max(tp_optimal) <= max(tp_fixed))
+        # arm
+        kernel_fixed = deepcopy(self.kernel_AArch64)
+        self.semantics_tx2.add_semantics(kernel_fixed)
+        kernel_optimal = deepcopy(kernel_fixed)
+        self.semantics_tx2.assign_optimal_throughput(kernel_optimal)
+        tp_fixed = self.semantics_tx2.get_throughput_sum(kernel_fixed)
+        tp_optimal = self.semantics_tx2.get_throughput_sum(kernel_optimal)
+        self.assertNotEqual(tp_fixed, tp_optimal)
+        self.assertTrue(max(tp_optimal) <= max(tp_fixed))
+
     def test_kernelDG_x86(self):
         #
         #  4