test(alt_registry): add test for registry index usage in package dependencies

Author: moabo3li

tests/testsuite/alt_registry.rs

@@ -315,6 +315,50 @@ Caused by:
         .run();
 }
 
+#[cargo_test]
+fn registry_index_allowed_in_registry_packages() {
+    registry::alt_init();
+
+    Package::new("base", "0.1.0").alternative(true).publish();
+
+    Package::new("intermediate", "0.1.0")
+        .alternative(true)
+        .registry_dep("base", "0.1.0")
+        .publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                intermediate = { version = "0.1.0", registry = "alternative" }
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("check")
+        .with_stderr_data(str![[r#"
+[UPDATING] `alternative` index
+[LOCKING] 2 packages to latest compatible versions
+[DOWNLOADING] crates ...
+[DOWNLOADED] intermediate v0.1.0 (registry `alternative`)
+[DOWNLOADED] base v0.1.0 (registry `alternative`)
+[CHECKING] base v0.1.0 (registry `alternative`)
+[CHECKING] intermediate v0.1.0 (registry `alternative`)
+[CHECKING] foo v0.0.1 ([ROOT]/foo)
+[FINISHED] `dev` profile [unoptimized + debuginfo] target(s) in [ELAPSED]s
+
+"#]])
+        .run();
+}
+
 #[cargo_test]
 fn cannot_publish_to_crates_io_with_registry_dependency() {
     let crates_io = registry::init();