Merge #390 checksums: Never skip checksumming phase

pungi/phases/image_checksum.py

@@ -25,6 +25,13 @@ class ImageChecksumPhase(PhaseBase):
         self.checksums = self.compose.conf['media_checksums']
         self.one_file = self.compose.conf['media_checksum_one_file']
 
+    def skip(self):
+        # Skipping this phase does not make sense:
+        #  * if there are no images, it doesn't do anything and is quick
+        #  * if there are images, they must have checksums computed or else
+        #    writing metadata will fail
+        return False
+
     def validate(self):
         errors = []
         try:

tests/test_imagechecksumphase.py

@@ -20,6 +20,11 @@ from tests.helpers import DummyCompose, PungiTestCase
 
 class TestImageChecksumPhase(PungiTestCase):
 
+    def test_phase_is_never_skipped(self):
+        compose = DummyCompose(self.topdir, {})
+        phase = ImageChecksumPhase(compose)
+        self.assertFalse(phase.skip())
+
     def test_config_skip_individual_with_multiple_algorithms(self):
         compose = DummyCompose(self.topdir, {
             'media_checksums': ['md5', 'sha1'],