Additional tests to cover selecting next release.

core/charm/repository/charmhub.go

@@ -526,7 +526,7 @@ func (c *CharmHubRepository) selectNextBasesFromReleases(releases []transport.Re
 		// If the user passed in a branch, but not enough information about the
 		// arch and series, then we can help by giving a better error message.
 		if origin.Channel != nil && origin.Channel.Branch != "" {
-			return nil, errors.Errorf("ambiguous arch and series with channel track/risk/branch. specify both arch and series along with channel.")
+			return nil, errors.Errorf("ambiguous arch and series with channel track/risk/branch. specify both arch and series along with channel")
 		}
 		// If the origin is empty, then we want to help the user out
 		// by display a series of suggestions to try.

core/charm/repository/charmhub_test.go

@@ -718,6 +718,7 @@ func (refreshConfigSuite) TestRefreshByID(c *gc.C) {
 
 type selectNextBaseSuite struct {
 	testing.IsolationSuite
+	logger *mocks.MockLogger
 }
 
 var _ = gc.Suite(&selectNextBaseSuite{})
@@ -773,6 +774,71 @@ func (selectNextBaseSuite) TestSelectNextBaseWithValidBases(c *gc.C) {
 	}})
 }
 
+func (selectNextBaseSuite) TestSelectNextBasesFromReleasesNoReleasesError(c *gc.C) {
+	channel := corecharm.MustParseChannel("stable/foo")
+	repo := new(CharmHubRepository)
+	_, err := repo.selectNextBasesFromReleases([]transport.Release{}, corecharm.Origin{
+		Channel: &channel,
+	})
+	c.Assert(err, gc.ErrorMatches, `no releases available`)
+}
+
+func (selectNextBaseSuite) TestSelectNextBasesFromReleasesAmbiguousMatchError(c *gc.C) {
+	channel := corecharm.MustParseChannel("stable/foo")
+	repo := new(CharmHubRepository)
+	_, err := repo.selectNextBasesFromReleases([]transport.Release{
+		{},
+	}, corecharm.Origin{
+		Channel: &channel,
+	})
+	c.Assert(err, gc.ErrorMatches, `ambiguous arch and series with channel track/risk/branch. specify both arch and series along with channel`)
+}
+
+func (s *selectNextBaseSuite) TestSelectNextBasesFromReleasesSuggestionError(c *gc.C) {
+	defer s.setupMocks(c).Finish()
+	repo := NewCharmHubRepository(s.logger, nil)
+
+	channel := corecharm.MustParseChannel("stable")
+	_, err := repo.selectNextBasesFromReleases([]transport.Release{{
+		Base: transport.Base{
+			Name:         "os",
+			Channel:      "series",
+			Architecture: "arch",
+		},
+		Channel: "stable",
+	}}, corecharm.Origin{
+		Channel: &channel,
+	})
+	c.Assert(err, gc.ErrorMatches, `no charm or bundle matching channel or platform`)
+}
+
+func (s *selectNextBaseSuite) TestSelectNextBasesFromReleasesSuggestion(c *gc.C) {
+	defer s.setupMocks(c).Finish()
+	repo := NewCharmHubRepository(s.logger, nil)
+
+	_, err := repo.selectNextBasesFromReleases([]transport.Release{{
+		Base: transport.Base{
+			Name:         "os",
+			Channel:      "20.04",
+			Architecture: "arch",
+		},
+		Channel: "stable",
+	}}, corecharm.Origin{
+		Platform: corecharm.Platform{
+			Architecture: "arch",
+		},
+	})
+	c.Assert(err, gc.ErrorMatches, `no charm or bundle matching channel or platform; suggestions: stable with focal`)
+}
+
+func (s *selectNextBaseSuite) setupMocks(c *gc.C) *gomock.Controller {
+	ctrl := gomock.NewController(c)
+	s.logger = mocks.NewMockLogger(ctrl)
+	s.logger.EXPECT().Errorf(gomock.Any(), gomock.Any()).AnyTimes()
+	s.logger.EXPECT().Tracef(gomock.Any(), gomock.Any()).AnyTimes()
+	return ctrl
+}
+
 type composeSuggestionsSuite struct {
 	testing.IsolationSuite
 	logger *mocks.MockLogger