=== modified file 'CHANGES.txt'
--- CHANGES.txt	2010-04-11 01:31:21 +0000
+++ CHANGES.txt	2010-04-11 02:17:01 +0000
@@ -4,6 +4,8 @@
 3.9.4 (unreleased)
 ==================
 
+- LP #497871:  Make testrunner run unit tests first.
+
 - LP #399394:  Added a ``--stop-on-error`` / ``--stop`` / ``-x`` option to
   the testrunner.
 

=== modified file 'src/zope/testing/testrunner/runner.py'
--- src/zope/testing/testrunner/runner.py	2010-04-11 01:31:21 +0000
+++ src/zope/testing/testrunner/runner.py	2010-04-11 02:11:03 +0000
@@ -31,6 +31,7 @@
 
 from zope.testing.testrunner.find import import_name
 from zope.testing.testrunner.find import name_from_layer, _layer_name_cache
+from zope.testing.testrunner.layer import UnitTests
 from zope.testing.testrunner.refcount import TrackRefs
 from zope.testing.testrunner.options import get_options
 import zope.testing.testrunner.coverage
@@ -784,6 +785,9 @@
     gathered.reverse()
     seen = {}
     result = []
+    if UnitTests in layers:
+        result.append(UnitTests)
+        gathered.remove(UnitTests)
     for layer in gathered:
         if layer not in seen:
             seen[layer] = 1

=== modified file 'src/zope/testing/testrunner/tests.py'
--- src/zope/testing/testrunner/tests.py	2010-04-06 02:02:54 +0000
+++ src/zope/testing/testrunner/tests.py	2010-04-11 02:10:41 +0000
@@ -163,8 +163,115 @@
     sys.modules.update(test.globs['saved-sys-info'][2])
 
 
+class Test_order_by_bases(unittest.TestCase):
+
+    def _callFUT(self, layers):
+        from zope.testing.testrunner.runner import order_by_bases
+        return order_by_bases(layers)
+
+    def test_empty(self):
+        self.assertEqual(list(self._callFUT(())), [])
+
+    def test_w_layer_no_bases(self):
+        class NoBases(object):
+            pass
+        result = self._callFUT([NoBases])
+        self.assertEqual(len(result), 1)
+        self.failUnless(result[0] is NoBases)
+
+    def test_w_layer_w_bases(self):
+        class OneBase(object):
+            pass
+        class AnotherBase(object):
+            pass
+        class Derived(OneBase, AnotherBase):
+            pass
+        result = self._callFUT([OneBase, AnotherBase, Derived])
+        self.assertEqual(len(result), 3)
+        self.failUnless(result[0] is AnotherBase)
+        self.failUnless(result[1] is OneBase)
+        self.failUnless(result[2] is Derived)
+
+    def test_unit_tests_first(self):
+        from zope.testing.testrunner.layer import UnitTests
+        class ALayer(object):
+            __module__ = 'a.b.c'
+            pass
+        class ZLayer(object):
+            __module__ = 'x.y.z'
+            pass
+        result = self._callFUT([ZLayer, ALayer, UnitTests])
+        self.assertEqual(len(result), 3)
+        self.failUnless(result[0] is UnitTests)
+        self.failUnless(result[1] is ALayer)
+        self.failUnless(result[2] is ZLayer)
+        result = self._callFUT([UnitTests, ALayer, ZLayer])
+        self.assertEqual(len(result), 3)
+        self.failUnless(result[0] is UnitTests)
+        self.failUnless(result[1] is ALayer)
+        self.failUnless(result[2] is ZLayer)
+        result = self._callFUT([ALayer, ZLayer, UnitTests])
+        self.assertEqual(len(result), 3)
+        self.failUnless(result[0] is UnitTests)
+        self.failUnless(result[1] is ALayer)
+        self.failUnless(result[2] is ZLayer)
+
+class Test_gather_layers(unittest.TestCase):
+
+    def _callFUT(self, layer, result):
+        from zope.testing.testrunner.runner import gather_layers
+        return gather_layers(layer, result)
+
+    def test_w_object(self):
+        result = []
+        self._callFUT(object, result)
+        self.assertEqual(len(result), 0)
+
+    def test_w_layer_no_bases(self):
+        class NoBases(object):
+            pass
+        result = []
+        self._callFUT(NoBases, result)
+        self.assertEqual(len(result), 1)
+        self.failUnless(result[0] is NoBases)
+
+    def test_w_layer_w_bases(self):
+        class OneBase(object):
+            pass
+        class AnotherBase(object):
+            pass
+        class Derived(OneBase, AnotherBase):
+            pass
+        result = []
+        self._callFUT(Derived, result)
+        self.assertEqual(len(result), 3)
+        self.failUnless(result[0] is Derived)
+        self.failUnless(result[1] is OneBase)
+        self.failUnless(result[2] is AnotherBase)
+
+    def test_w_layer_w_diamond(self):
+        class Base(object):
+            pass
+        class Ammonia(Base):
+            pass
+        class Lye(Base):
+            pass
+        class Boom(Ammonia, Lye):
+            pass
+        result = []
+        self._callFUT(Boom, result)
+        self.assertEqual(len(result), 5)
+        self.failUnless(result[0] is Boom)
+        self.failUnless(result[1] is Ammonia)
+        self.failUnless(result[2] is Base)
+        self.failUnless(result[3] is Lye)
+        self.failUnless(result[4] is Base)
+
+
 def test_suite():
     suites = [
+        unittest.makeSuite(Test_order_by_bases),
+        unittest.makeSuite(Test_gather_layers),
         doctest.DocFileSuite(
         'testrunner-arguments.txt',
         'testrunner-coverage.txt',