tests: add overriding repo tests for Config.add_repo() support

Author: radhermit

tests/test_config.py

@@ -74,7 +74,7 @@ def test_add_repo_path_fake(self, config, tmp_path):
         r = config.add_repo(f)
         assert len(r) == 3
 
-    def test_add_repo(self, config):
+    def test_add_repo(self, config, make_ebuild_repo):
         assert not config.repos
         r1 = FakeRepo(id="r1", priority=1)
         r2 = FakeRepo(id="r2", priority=2)
@@ -86,6 +86,19 @@ def test_add_repo(self, config):
         # re-adding a repo succeeds
         assert r1 == config.add_repo(r1)
 
+        # overriding a repo fails
+        r = FakeRepo(["cat/pkg-1"], id="r1")
+        with pytest.raises(ConfigError, match="can't override existing repos: r1"):
+            config.add_repo(r)
+
+        # external repos with matching names can be added since they're keyed via path
+        r = make_ebuild_repo(id="r2")
+        config.add_repo(r, external=True)
+
+        # but will fail if not added as an external repo
+        with pytest.raises(ConfigError, match="can't override existing repos: r2"):
+            config.add_repo(r, external=False)
+
     def test_repo_sets(self, config, make_ebuild_repo, make_fake_repo):
         # empty
         assert config.repos.all == RepoSet()