diff --git a/compiler/tests/21_hspice_delay_test.py b/compiler/tests/21_hspice_delay_test.py
index 87b6576e..8c52afdb 100644
--- a/compiler/tests/21_hspice_delay_test.py
+++ b/compiler/tests/21_hspice_delay_test.py
@@ -23,7 +23,9 @@ class timing_sram_test(unittest.TestCase):
         import characterizer
         reload(characterizer)
         from characterizer import delay
-        self.assertTrue(OPTS.spice_exe)
+        if not OPTS.spice_exe:
+            self.error("Could not find {} simulator.".format(OPTS.spice_name))
+            self.assertTrue(OPTS.spice_exe)
 
         import sram
 
diff --git a/compiler/tests/21_hspice_setuphold_test.py b/compiler/tests/21_hspice_setuphold_test.py
index a0d9df02..b246f5c5 100644
--- a/compiler/tests/21_hspice_setuphold_test.py
+++ b/compiler/tests/21_hspice_setuphold_test.py
@@ -23,7 +23,10 @@ class timing_setup_test(unittest.TestCase):
         import characterizer
         reload(characterizer)
         from characterizer import setup_hold
-        self.assertTrue(OPTS.spice_exe)
+        if not OPTS.spice_exe:
+            self.error("Could not find {} simulator.".format(OPTS.spice_name))
+            self.assertTrue(OPTS.spice_exe)
+            
 
         import sram
         import tech
diff --git a/compiler/tests/21_ngspice_delay_test.py b/compiler/tests/21_ngspice_delay_test.py
index 45249cd6..b313d0ec 100644
--- a/compiler/tests/21_ngspice_delay_test.py
+++ b/compiler/tests/21_ngspice_delay_test.py
@@ -23,7 +23,9 @@ class timing_sram_test(unittest.TestCase):
         import characterizer
         reload(characterizer)
         from characterizer import delay
-        self.assertTrue(OPTS.spice_exe)
+        if not OPTS.spice_exe:
+            self.error("Could not find {} simulator.".format(OPTS.spice_name))
+            self.assertTrue(OPTS.spice_exe)
 
         import sram
 
diff --git a/compiler/tests/21_ngspice_setuphold_test.py b/compiler/tests/21_ngspice_setuphold_test.py
index 185c877c..6b1c4d8c 100644
--- a/compiler/tests/21_ngspice_setuphold_test.py
+++ b/compiler/tests/21_ngspice_setuphold_test.py
@@ -23,7 +23,9 @@ class timing_setup_test(unittest.TestCase):
         import characterizer
         reload(characterizer)
         from characterizer import setup_hold
-        self.assertTrue(OPTS.spice_exe)
+        if not OPTS.spice_exe:
+            self.error("Could not find {} simulator.".format(OPTS.spice_name))
+            self.assertTrue(OPTS.spice_exe)
         
         import sram
         import tech