add test for the failing case

test-data/recipes/pin_subpackage/recipe.yaml

@@ -0,0 +1,23 @@
+# regression test that pin subpackage works with `my.package`
+context:
+  name: my.package
+  version: 0.1.0
+
+recipe:
+  version: ${{ version }}
+build:
+  number: 0
+
+outputs:
+  - package:
+      name: ${{ name }}
+    build:
+      noarch: generic
+
+  - package:
+      name: ${{ name }}-a
+    build:
+      noarch: generic
+    requirements:
+      run:
+        - ${{ pin_subpackage(name, exact=true) }}

test/end-to-end/test_simple.py

@@ -998,3 +998,14 @@ def test_env_vars_override(rattler_build: RattlerBuild, recipes: Path, tmp_path:
         "variant": "pybind11-abi",
         "spec": "pybind11-abi 4.*",
     }
+
+
+def test_pin_subpackage(
+    rattler_build: RattlerBuild, recipes: Path, tmp_path: Path, snapshot_json
+):
+    rattler_build.build(
+        recipes / "pin_subpackage",
+        tmp_path,
+    )
+    pkg = get_extracted_package(tmp_path, "my.package-a")
+    assert (pkg / "info/index.json").exists()