pkgmgr/tests/integration/test_install_repos.md

Integration Test: Command Resolution & Link Creation

File: tests/integration/test_install_repos_integration.py

This integration test validates the end-to-end behavior of the pkgmgr installation pipeline:

1. Repository selection
2. Verification
3. Command resolution (resolve_command_for_repo)
4. Symlink creation (create_ink)
5. Installer execution order and skipping rules

The test sets up two repositories:

Repository	Environment Condition	Expected Behavior
repo-system	/usr/bin/tool-system exists	System binary → NO symlink
repo-nix	Nix profile contains tool-nix	Link → ~/.nix-profile/bin/tool-nix

This confirms that pkgmgr respects system package managers, prefers Nix over fallback logic, and creates or skips symlinks appropriately.

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🔧 Command Selection Flowchart

The integration test verifies that pkgmgr follows this exact decision tree:

flowchart TD

A[Start: install_repos()] --> B(resolve_command_for_repo)

B --> C{Explicit command in repo config?}
C -- Yes --> C1[Return explicit command]
C -- No --> D

D --> E{System binary under /usr/?}
E -- Yes --> E1[Return None → NO symlink]
E -- No --> F

F --> G{Nix profile binary exists?}
G -- Yes --> G1[Return Nix binary]
G -- No --> H

H --> I{Python/non-system PATH binary?}
I -- Yes --> I1[Return PATH binary]
I -- No --> J

J --> K{main.sh/main.py in repo?}
K -- Yes --> K1[Return fallback script]
K -- No --> L[Error: No command found]

L --> X[Abort installation of this repo]

C1 --> M[create_ink → create symlink]
G1 --> M
I1 --> M
K1 --> M

E1 --> N[Skip symlink creation]

The integration test specifically checks branches:

• System binary → skip
• Nix binary → create link

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📐 Behavior Matrix (Simplified Priority Model)

Priority	Layer / Condition	Action	Link Created?
1	Explicit command in repo config	Use it	✅ Yes
2	System binary under /usr/bin/...	Respect OS	❌ No
3	Nix profile binary exists	Use it	✅ Yes
4	Non-system PATH binary	Use it	✅ Yes
5	Repo fallback (main.sh / main.py)	Use it	✅ Yes
6	None of the above	Raise error	❌ No

The integration test hits row 2 and 3.

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🧪 What This Integration Test Ensures

✔ Correct orchestration

install_repos() calls components in the correct sequence and respects outputs from each stage.

✔ Correct command resolution

The test asserts that:

• System binaries suppress symlink creation.
• Nix binaries produce symlinks even if PATH is empty.

✔ Correct linking behavior

For the Nix repo:

• A symlink is created under the bin_dir.
• The symlink points exactly to ~/.nix-profile/bin/<identifier>.

✔ Isolation

No real system binaries or actual Nix installation are required—the test uses deterministic patches.

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🧩 Additional Notes

• The integration test covers only the positive Nix case and the system binary skip case. More tests can be added later for:

  • Python binary resolution
  • Fallback to main.py
  • Error case when no command can be resolved

• The test intentionally uses a temporary HOME directory to simulate isolated Nix profiles.

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✅ Summary

This integration test validates that:

• pkgmgr does not overwrite or override system binaries
• Nix takes precedence over PATH-based tools
• The symlink layer works correctly
• The installer pipeline continues normally even when command resolution skips symlink creation

The file provides a reliable foundation for confirming that command resolution, linking, and installation orchestration are functioning exactly as designed.