diff --git a/autopkgtest.py b/autopkgtest.py
index 6b75f6e..855e84c 100644
--- a/autopkgtest.py
+++ b/autopkgtest.py
@@ -307,8 +307,14 @@ class AutoPackageTest(object):
         # didn't see in britney yet
         ver_trig_results = self.test_results.get(src, {}).get(arch, [None, {}, None])[1]
         unstable_ver = self.britney.sources['unstable'][src][VERSION]
-        for result_ver in [ver, unstable_ver]:
-            if result_ver not in ver_trig_results or apt_pkg.version_compare(result_ver, ver) < 0:
+        try:
+            testing_ver = self.britney.sources['testing'][src][VERSION]
+        except KeyError:
+            testing_ver = unstable_ver
+        for result_ver in set([testing_ver, ver, unstable_ver]):
+            # result_ver might be < ver here; that's okay, if we already have a
+            # result for trigsrc/trigver we don't need to re-run it again
+            if result_ver not in ver_trig_results:
                 continue
             for trigger in ver_trig_results[result_ver]:
                 (tsrc, tver) = trigger.split('/', 1)
@@ -646,18 +652,25 @@ class AutoPackageTest(object):
                 try:
                     (_, ver_map, ever_passed) = self.test_results[testsrc][arch]
 
-                    # we prefer passing tests for the specified testver; but if
-                    # they fail, we also check for a result > testver, as test
-                    # runs might see built versions which we didn't see in
-                    # britney yet
-                    try:
-                        trigger_results = ver_map[testver]
-                        if not trigger_results[trigger]:
-                            raise KeyError
-                    except KeyError:
-                        (testver, trigger_results) = latest_item(ver_map, testver)
+                    # check if we have a result for any version of testsrc that
+                    # was triggered for trigsrc/trigver; we prefer PASSes, as
+                    # it could be that an unrelated package upload could break
+                    # testsrc's tests at a later point
+                    status = None
+                    for ver, trigger_results in ver_map.items():
+                        try:
+                            status = trigger_results[trigger]
+                            testver = ver
+                            # if we found a PASS, we can stop searching
+                            if status is True:
+                                break
+                        except KeyError:
+                            pass
+
+                    if status is None:
+                        # no result? go to "still running" below
+                        raise KeyError
 
-                    status = trigger_results[trigger]
                     if status:
                         result = 'PASS'
                     else:
diff --git a/tests/test_autopkgtest.py b/tests/test_autopkgtest.py
index 5a1a16d..d653993 100755
--- a/tests/test_autopkgtest.py
+++ b/tests/test_autopkgtest.py
@@ -1087,6 +1087,44 @@ lightgreen 1 i386 green 3
             })
         self.assertEqual(self.pending_requests, '')
 
+    def test_new_runs_dont_clobber_pass(self):
+        '''passing once is sufficient
+
+        If a test succeeded once for a particular version and trigger,
+        subsequent failures (which might be triggered by other unstable
+        uploads) should not invalidate the PASS, as that new failure is the
+        fault of the new upload, not the original one.
+        '''
+        # new libc6 works fine with green
+        self.swift.set_results({'autopkgtest-series': {
+            'series/i386/g/green/20150101_100000@': (0, 'green 1', {'custom_environment': ['ADT_TEST_TRIGGERS=libc6/2']}),
+            'series/amd64/g/green/20150101_100000@': (0, 'green 1', {'custom_environment': ['ADT_TEST_TRIGGERS=libc6/2']}),
+        }})
+
+        self.do_test(
+            [('libc6', {'Version': '2'}, None)],
+            {'libc6': (True, {'green 1': {'amd64': 'PASS', 'i386': 'PASS'}})})
+        self.assertEqual(self.pending_requests, '')
+
+        # new green fails; that's not libc6's fault though, so it should stay
+        # valid
+        self.swift.set_results({'autopkgtest-series': {
+            'series/i386/g/green/20150101_100100@': (4, 'green 2', {'custom_environment': ['ADT_TEST_TRIGGERS=green/2']}),
+            'series/amd64/g/green/20150101_100100@': (4, 'green 2', {'custom_environment': ['ADT_TEST_TRIGGERS=green/2']}),
+        }})
+        self.do_test(
+            [('libgreen1', {'Version': '2', 'Source': 'green', 'Depends': 'libc6'}, 'autopkgtest')],
+            {'green': (False, {'green 2': {'amd64': 'REGRESSION', 'i386': 'REGRESSION'}}),
+             'libc6': (True, {'green 1': {'amd64': 'PASS', 'i386': 'PASS'}}),
+            })
+        self.assertEqual(
+            self.amqp_requests,
+            set(['debci-series-i386:darkgreen {"triggers": ["green/2"]}',
+                 'debci-series-amd64:darkgreen {"triggers": ["green/2"]}',
+                 'debci-series-i386:lightgreen {"triggers": ["green/2"]}',
+                 'debci-series-amd64:lightgreen {"triggers": ["green/2"]}',
+                ]))
+
     def test_remove_from_unstable(self):
         '''broken package gets removed from unstable'''