diff --git a/tests/call_error_test.py b/tests/call_error_test.py
index 72d3c46e..baebd1eb 100644
--- a/tests/call_error_test.py
+++ b/tests/call_error_test.py
@@ -1,4 +1,3 @@
-import os
 import pickle
 import sys
 
diff --git a/tests/error_test.py b/tests/error_test.py
index 7f890875..2eefd567 100644
--- a/tests/error_test.py
+++ b/tests/error_test.py
@@ -1,15 +1,8 @@
 
-import logging
-import subprocess
-import time
-import zlib
-
 import unittest2
 
 import testlib
-import mitogen.master
-import mitogen.parent
-import mitogen.utils
+import mitogen.core
 
 
 class ConstructorTest(testlib.TestCase):
diff --git a/tests/router_test.py b/tests/router_test.py
index 351d7ace..51035d54 100644
--- a/tests/router_test.py
+++ b/tests/router_test.py
@@ -1,5 +1,3 @@
-import logging
-import subprocess
 import time
 import zlib
 
diff --git a/tests/serialization_test.py b/tests/serialization_test.py
index d8c54c59..ffbdf694 100644
--- a/tests/serialization_test.py
+++ b/tests/serialization_test.py
@@ -1,11 +1,4 @@
 
-try:
-    from io import StringIO
-    from io import BytesIO
-except ImportError:
-    from StringIO import StringIO as StringIO
-    from StringIO import StringIO as BytesIO
-
 import pickle
 import unittest2
 
diff --git a/tests/signals_test.py b/tests/signals_test.py
new file mode 100644
index 00000000..5957d3fa
--- /dev/null
+++ b/tests/signals_test.py
@@ -0,0 +1,45 @@
+
+import unittest2
+
+import testlib
+import mitogen.core
+
+
+class Thing():
+    pass
+
+
+class ListenFireTest(testlib.TestCase):
+    def test_no_args(self):
+        thing = Thing()
+        latch = mitogen.core.Latch()
+        mitogen.core.listen(thing, 'event',
+            lambda: latch.put('event fired'))
+
+        mitogen.core.fire(thing, 'event')
+        self.assertEquals('event fired', latch.get())
+        self.assertTrue(latch.empty())
+
+    def test_with_args(self):
+        thing = Thing()
+        latch = mitogen.core.Latch()
+        mitogen.core.listen(thing, 'event', latch.put)
+        mitogen.core.fire(thing, 'event', 'event fired')
+        self.assertEquals('event fired', latch.get())
+        self.assertTrue(latch.empty())
+
+    def test_two_listeners(self):
+        thing = Thing()
+        latch = mitogen.core.Latch()
+        latch2 = mitogen.core.Latch()
+        mitogen.core.listen(thing, 'event', latch.put)
+        mitogen.core.listen(thing, 'event', latch2.put)
+        mitogen.core.fire(thing, 'event', 'event fired')
+        self.assertEquals('event fired', latch.get())
+        self.assertEquals('event fired', latch2.get())
+        self.assertTrue(latch.empty())
+        self.assertTrue(latch2.empty())
+
+
+if __name__ == '__main__':
+    unittest2.main()
diff --git a/tests/types_test.py b/tests/types_test.py
index 2f0b1306..bd243949 100644
--- a/tests/types_test.py
+++ b/tests/types_test.py
@@ -26,14 +26,14 @@ class BlobTest(testlib.TestCase):
 
     def test_decays_on_constructor(self):
         blob = self.make()
-        self.assertEquals(b('x')*128, mitogen.core.BytesType(blob))
+        self.assertEquals(b('x') * 128, mitogen.core.BytesType(blob))
 
     def test_decays_on_write(self):
         blob = self.make()
         io = BytesIO()
         io.write(blob)
         self.assertEquals(128, io.tell())
-        self.assertEquals(b('x')*128, io.getvalue())
+        self.assertEquals(b('x') * 128, io.getvalue())
 
     def test_message_roundtrip(self):
         blob = self.make()