fix(installation-manager): un-ignore test_add_remove_installer

Add the __add_installer test seam that registers an installer as a
pre-built Rc handle, so the test can reproduce PHP's object-identity
semantics (assertSame / removeInstaller) via Rc::ptr_eq; add_installer
cannot serve because Rc::from(Box) reallocates, losing the caller's
pointer identity.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/crates/shirabe/src/installer/installation_manager.rs b/crates/shirabe/src/installer/installation_manager.rs
index 6c46754c..2d60997c 100644
--- a/crates/shirabe/src/installer/installation_manager.rs
+++ b/crates/shirabe/src/installer/installation_manager.rs
@@ -133,6 +133,15 @@ impl InstallationManager {
         self.cache = std::cell::RefCell::new(IndexMap::new());
     }
 
+    /// For testing only: adds an installer as a pre-built shared handle, so the caller keeps an
+    /// identity handle usable for PHP `assertSame`-style comparisons (`Rc::ptr_eq`) and for
+    /// `remove_installer`. `add_installer` cannot serve because `Rc::from(Box)` reallocates,
+    /// losing the caller's pointer identity.
+    pub fn __add_installer(&mut self, installer: std::rc::Rc<dyn InstallerInterface>) {
+        array_unshift(&mut self.installers, installer);
+        self.cache = std::cell::RefCell::new(IndexMap::new());
+    }
+
     /// Removes installer
     pub fn remove_installer(&mut self, installer: &dyn InstallerInterface) {
         let target = installer as *const dyn InstallerInterface as *const ();