scanner: add refresh_config config item for buildserver

Includes some cosmetic changes from black.

examples/config.yml

@@ -373,3 +373,9 @@
 #   - suss
 #   - exodus
 #   - https://example.com/signatures.json
+
+# The scanner can use signature sources from the internet. These are
+# cached locally.  To force them to be refreshed from the network on
+# every run, set this to true:
+#
+# refresh_scanner: true

fdroidserver/scanner.py

@@ -325,15 +325,15 @@ class SUSSDataController(SignatureDataController):
         self.set_data(json.loads(SUSS_DEFAULT))
 
 
-class ScannerTool():
+class ScannerTool:
     def __init__(self):
-
         # we could add support for loading additional signature source
         # definitions from config.yml here
 
         self.scanner_data_lookup()
 
-        if options and options.refresh_scanner:
+        config = common.get_config()
+        if (options and options.refresh_scanner) or config.get('refresh_scanner'):
             self.refresh()
 
         self.load()

tests/scanner.TestCase

@@ -704,6 +704,20 @@ class Test_SignatureDataController(unittest.TestCase):
 
 
 class Test_ScannerTool(unittest.TestCase):
+    def setUp(self):
+        fdroidserver.common.options = None
+        fdroidserver.common.config = None
+        self.basedir = os.path.join(localmodule, 'tests')
+        os.chdir(self.basedir)
+        self._td = mkdtemp()
+        self.testdir = self._td.name
+
+    def tearDown(self):
+        fdroidserver.common.options = None
+        fdroidserver.common.config = None
+        os.chdir(self.basedir)
+        self._td.cleanup()
+
     def test_load(self):
         st = mock.Mock()
         st.sdcs = [mock.Mock(), mock.Mock()]
@@ -711,7 +725,8 @@ class Test_ScannerTool(unittest.TestCase):
         st.sdcs[0].load.assert_called_once_with()
         st.sdcs[1].load.assert_called_once_with()
 
-    def test_refresh_default(self):
+    def test_refresh_no_options_or_config(self):
+        """This simulates what happens when running something like scan_source()"""
         with mock.patch('fdroidserver.scanner.ScannerTool.refresh') as refresh:
             fdroidserver.scanner.ScannerTool()
             refresh.assert_not_called()
@@ -730,6 +745,22 @@ class Test_ScannerTool(unittest.TestCase):
             fdroidserver.scanner.ScannerTool()
             refresh.assert_not_called()
 
+    def test_refresh_from_config(self):
+        os.chdir(self.testdir)
+        pathlib.Path('config.yml').write_text('refresh_scanner: true')
+        with mock.patch('fdroidserver.scanner.ScannerTool.refresh') as refresh:
+            fdroidserver.scanner.ScannerTool()
+            refresh.assert_called_once()
+
+    def test_refresh_options_overrides_config(self):
+        fdroidserver.scanner.options = mock.Mock()
+        fdroidserver.scanner.options.refresh_scanner = True
+        os.chdir(self.testdir)
+        pathlib.Path('config.yml').write_text('refresh_scanner: false')
+        with mock.patch('fdroidserver.scanner.ScannerTool.refresh') as refresh:
+            fdroidserver.scanner.ScannerTool()
+            refresh.assert_called_once()
+
 
 class Test_main(unittest.TestCase):
     def setUp(self):