Fix KeyError crash for sources which are only in unstable

The previous commit introduced a KeyError crash in tests_for_source() for
packages which are unbuilt/uninstallable and only present in unstable.

Ignore these in tests_for_source() as they can't possibly be a regression for
their dependencies, and there is no sensible way to run a test for them.

autopkgtest.py

@@ -174,9 +174,14 @@ class AutoPackageTest(object):
                 # works, then the unstable src does not break the testing
                 # rdep_src and is fine
                 if rdep_src in self.excludes:
+                    try:
                         rdep_src_info = self.britney.sources['testing'][rdep_src]
                         self.log_verbose('Reverse dependency %s of %s/%s is unbuilt or uninstallable, running test against testing version %s' %
                                          (rdep_src, src, ver, rdep_src_info[VERSION]))
+                    except KeyError:
+                        self.log_verbose('Reverse dependency %s of %s/%s is unbuilt or uninstallable and not present in testing, ignoring' %
+                                         (rdep_src, src, ver))
+                        continue
                 else:
                     rdep_src_info = sources_info[rdep_src]
                 if rdep_src_info[AUTOPKGTEST] or self.has_autodep8(rdep_src_info):

tests/test_autopkgtest.py

@@ -415,6 +415,38 @@ lightgreen 1 i386 green 2
         self.assertEqual(self.amqp_requests,
                          set(['debci-series-amd64:lightgreen', 'debci-series-i386:lightgreen']))
 
+    def test_rdepends_unbuilt_unstable_only(self):
+        '''Unbuilt reverse dependency which is not in testing'''
+
+        self.swift.set_results({'autopkgtest-series': {
+            'series/i386/d/darkgreen/20150101_100000@': (0, 'darkgreen 1'),
+            'series/amd64/d/darkgreen/20150101_100001@': (0, 'darkgreen 1'),
+            'series/i386/l/lightgreen/20150101_100000@': (0, 'lightgreen 1'),
+            'series/amd64/l/lightgreen/20150101_100000@': (0, 'lightgreen 1'),
+            'series/i386/g/green/20150101_020000@': (0, 'green 1'),
+            'series/amd64/g/green/20150101_020000@': (0, 'green 1'),
+            'series/i386/g/green/20150101_100200@': (0, 'green 2'),
+            'series/amd64/g/green/20150101_100201@': (0, 'green 2'),
+        }})
+        # run britney once to pick up previous results
+        self.do_test(
+            [('libgreen1', {'Version': '2', 'Source': 'green', 'Depends': 'libc6'}, 'autopkgtest')],
+            VALID_CANDIDATE)
+        os.unlink(self.fake_amqp)
+
+        # add new uninstallable brokengreen; should not run test at all
+        self.do_test(
+            [('brokengreen', {'Version': '1', 'Depends': 'libgreen1, nonexisting'}, 'autopkgtest')],
+            VALID_CANDIDATE,
+            [r'\bgreen\b.*>1</a> to .*>2<',
+             r'\bbrokengreen\b.*- to .*>1<',
+             r'autopkgtest for green 2: .*amd64.*Pass.*i386.*Pass',
+             r'autopkgtest for darkgreen 1: .*amd64.*Pass.*i386.*Pass',
+             'Not considered',  # for brokengreen
+             r'brokengreen/amd64 unsatisfiable Depends: nonexisting'],
+            ['autopkgtest for brokengreen'])
+        self.assertEqual(self.amqp_requests, set())
+
     def test_hint_force_badtest(self):
         '''force-badtest hint'''