Skill: App/Test Project Layout Diagnosis

Purpose

Diagnose and fix Business Central AL repositories where the main app and test app coexist in the same repository and may be compiled or resolved incorrectly.

When to Load

This skill should be loaded when:

• The main app build reports errors from test/src/
• AL0297 appears on test objects using the main app ID range
• AL0185 appears for Library Assert, Library - Sales, Library - Inventory, or Library - Random
• A nested test/app.json is not recognized
• A .code-workspace with app/test roots needs review
• The repo layout mixes a root app and a nested test project

Core Patterns

Pattern 1: Cross-Project Contamination Signal

If the main app build reports errors from test/src/ and the test object IDs are validated against the root app ID range, the compiler is discovering test sources from the main app tree.

Typical signal:

test/src/BSSIdempotencyTests.Codeunit.al(1,10): error AL0297:
The application object identifier '50804' is not valid.
It must be within the allowed ranges '[50680..50779]'.

Pattern 2: Dependency Audit for Test Libraries

When test code uses Library Assert, Library - Sales, Library - Inventory, or Library - Random, audit these dependencies in the test project:

• Application Test Library
• Library Assert
• Tests-TestLibraries
• System Application Test Library

Pattern 3: Isolation Strategy

Preferred:

• Physically separate app and test projects as sibling folders.

Fallback when layout cannot change:

• Add a test-only preprocessor symbol in the test app.json.
• Wrap test source files so the root app build cannot see them.

Pattern 4: Workspace Is Not a Compiler Boundary

Changing root order or files.exclude can improve editor behavior, but it does not change which files the main app compiler can discover from the physical project tree.

Workflow

Step 1: Inspect Project Boundaries

Read the root app.json, the test app.json, the .code-workspace, and list the repo root. Confirm whether test/ is nested under the main app root.

Step 2: Correlate Symptoms With Cause

• AL0297 on 508xx with the root app range usually means the main app is seeing test sources.
• AL0185 on test libraries usually means missing dependencies, wrong manifest resolution, or both.

Step 3: Choose the Fix

• If layout can change: move app and test into sibling folders.
• If layout cannot change: enforce compile isolation via preprocessor or an equivalent build barrier.
• Add missing Microsoft test dependencies in the test manifest.

Step 4: Validate Both Builds

Build the root app.json and the test app.json separately.

Success criteria:

• The root build ignores test sources.
• The test build resolves its own test libraries.

References

• https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-json-files
• https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-work-workspace-projects-references
• https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/devenv-multi-root-workspaces

Constraints

• This skill diagnoses layout, manifest, dependency, and workspace issues. It does not replace skill-testing for writing or refactoring test logic.
• Do not use Explorer hiding as a substitute for compile isolation.
• Prefer root-cause fixes over suppressing diagnostics or moving files ad hoc.