[M8] cargoxx-pkgs as a flake: cargoxx add → string-form dep

Wrapper: fix cache.nixos.org-1 key; drop AppImage; pin publish to mozart/cargoxx-pkgs.

tests/manifest_write.cpp

@@ -138,3 +138,44 @@ TEST_CASE("write fails when the target directory does not exist",
     auto r = write(m, "/nonexistent/dir/Cargoxx.toml");
     REQUIRE_FALSE(r.has_value());
 }
+
+TEST_CASE("write round-trips a path-form dependency", "[manifest][write]") {
+    Manifest m{
+        pkg("consumer", "0.1.0"),
+        {Dependency{
+            .name = "mylib",
+            .version_spec = "*",
+            .components = {},
+            .source = cargoxx::manifest::DepSource::CargoxxPath,
+            .path = "../mylib",
+        }},
+        {},
+    };
+    REQUIRE(round_trip(m) == m);
+}
+
+TEST_CASE("write round-trips a git-form dependency", "[manifest][write]") {
+    Manifest m{
+        pkg("consumer", "0.1.0"),
+        {Dependency{
+            .name = "mylib",
+            .version_spec = "*",
+            .components = {},
+            .source = cargoxx::manifest::DepSource::CargoxxGit,
+            .git_url = "https://gitea.example/me/mylib",
+            .git_rev = "0123456789012345678901234567890123456789",
+        }},
+        {},
+    };
+    REQUIRE(round_trip(m) == m);
+}
+
+TEST_CASE("write round-trips description/repository/homepage",
+          "[manifest][write]") {
+    auto p = pkg("foo", "0.1.0");
+    p.description = "demo library";
+    p.repository = "https://gitea.example/me/foo";
+    p.homepage = "https://example.com/foo";
+    Manifest m{p, {}, {}};
+    REQUIRE(round_trip(m) == m);
+}