GMVM.EnergyTracker — Fixi Demo Sandbox

ASP.NET Core 9 Web API for energy meter readings, deliberately seeded with 3 intentional defects so that Fixi can be demonstrated end-to-end against a realistic .NET codebase.

The domain — meter readings for energy distribution — matches GlobalMVM's actual sector and clients (EPM, ISAGEN, XM, Veolia). The defects are seeded across Domain, Infrastructure, and Api to exercise Fixi's classification, root-cause analysis, and PR creation across architectural layers.

Disponible también en español: README.es.md

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⚠️ Read this first

This repository ships with broken code on purpose. There are 3 intentional bugs (one bug, one performance, one security) and a corresponding set of failing tests. Do not "fix" them by hand — that defeats the demo. The whole point is to invoke Fixi and watch it diagnose, branch, fix, test, and PR each one.

The defects are documented as Azure DevOps-style work items in docs/issues/.

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What this is

A small but realistic ASP.NET Core 9 Web API:

• Domain: Medidor, Lectura, Usuario entities + CalculadoraConsumo, IMedidorService
• Infrastructure: EF Core 9 + SQLite (zero setup), EnergyTrackerDbContext, deterministic seed (50 medidores, 5000 lecturas)
• Api: JWT Bearer auth, controllers for Medidores, Usuarios, Admin, Swagger UI
• Tests: xUnit unit + integration tests using WebApplicationFactory<Program> and an isolated SQLite :memory: connection per test class

Layer	Project
Web API	src/GMVM.EnergyTracker.Api
Business logic	src/GMVM.EnergyTracker.Domain
Data access	src/GMVM.EnergyTracker.Infrastructure
Tests	tests/GMVM.EnergyTracker.Tests

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The 3 seeded defects

#	Type	Work Item	Where	Acceptance test
1	bug	WI-101	Domain/Services/CalculadoraConsumo.cs	CalculadoraConsumoTests.Calcular_DosLecturasMismoDia_NoDebeLanzarExcepcion
2	performance	WI-102	Infrastructure/Services/MedidorService.cs	MedidoresEndpointTests.Listar_LatenciaP95_DebeSerMenorA500ms
3	security	WI-103	Api/Controllers/AdminController.cs	AdminEndpointSecurityTests.ResetearLecturas_* (3 tests)

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Prerequisites

• .NET 9 SDK (dotnet --version should report 9.0.x)
• A Claude Code session with the fix-issue skill installed at .claude/skills/fix-issue/
• Optional for the Azure DevOps path: az CLI with the azure-devops extension and a sandbox ADO project

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Quick start

# Clone
git clone https://github.com/lotsofcontext/fixi-demo-dotnet
cd fixi-demo-dotnet

# Restore and build
dotnet restore
dotnet build

# Run the failing test suite — you should see 5 red, 3 green
dotnet test

Expected baseline output:

Failed!  -  Failed:     5, Passed:     3, Skipped:     0, Total:     8

The 5 failures are evidence of the seeded defects. Fixi will turn each one green.

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Running Fixi against the seeded issues

Open a Claude Code session in the repo root, then invoke the fix-issue skill against each work item:

/fix-issue docs/issues/WI-101-bug-lectura-negativa.md

Fixi will:

1. Safety Gate (Step 0) — verify it is in fixi-demo-dotnet, working tree is clean, and master is the current branch
2. Parse (Step 1) — extract title, body, priority, and tags from the work item markdown
3. Classify (Step 2) — bug (high confidence — keywords: "500", "DivideByZero", "exception")
4. Root cause analysis (Step 4) — grep CalculadoraConsumo, read the file, identify the .Days integer division
5. Branch (Step 5) — fix/WI-101-consumo-negativo-mismo-dia off master
6. Implement (Step 6) — minimal change: guard for same-day case
7. Test (Step 7) — dotnet test → 4 failures left (down from 5)
8. PR (Step 8) — gh pr create with full template (or az repos pr create if running against an Azure Repos mirror)
9. Tracking (Step 9) — updates the configured tracking destinations

Repeat for WI-102 (performance) and WI-103 (security). Note that WI-103 will force GUIDED mode automatically because Fixi escalates security issues for human review at every step.

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Project structure

fixi-demo-dotnet/
├── README.md                     # This file (English)
├── README.es.md                  # Spanish version
├── CLAUDE.md                     # Conventions Fixi reads in Step 0
├── global.json                   # Pins .NET 9 SDK
├── .editorconfig
├── .gitignore
├── GMVM.EnergyTracker.sln
│
├── src/
│   ├── GMVM.EnergyTracker.Api/
│   │   ├── Program.cs            # JWT auth, EF, Swagger, seed on startup
│   │   ├── Controllers/
│   │   │   ├── MedidoresController.cs    # [Authorize] (correct pattern)
│   │   │   ├── UsuariosController.cs     # [Authorize] (correct pattern)
│   │   │   └── AdminController.cs        # NO [Authorize] — WI-103 bug
│   │   ├── appsettings.json
│   │   └── appsettings.Development.json
│   │
│   ├── GMVM.EnergyTracker.Domain/
│   │   ├── Models/
│   │   │   ├── Medidor.cs
│   │   │   ├── Lectura.cs
│   │   │   └── Usuario.cs
│   │   ├── Dtos/
│   │   │   └── MedidorListItem.cs
│   │   └── Services/
│   │       ├── ICalculadoraConsumo.cs
│   │       ├── CalculadoraConsumo.cs    # WI-101 bug lives here
│   │       └── IMedidorService.cs
│   │
│   └── GMVM.EnergyTracker.Infrastructure/
│       ├── EnergyTrackerDbContext.cs
│       ├── Seed/SeedData.cs
│       └── Services/
│           └── MedidorService.cs        # WI-102 N+1 lives here
│
├── tests/
│   └── GMVM.EnergyTracker.Tests/
│       ├── Unit/
│       │   └── CalculadoraConsumoTests.cs       # WI-101 regression
│       └── Integration/
│           ├── TestWebApplicationFactory.cs     # SQLite :memory: setup
│           ├── JwtTokenHelper.cs                # signed JWTs for tests
│           ├── MedidoresEndpointTests.cs        # WI-102 latency guard
│           └── AdminEndpointSecurityTests.cs    # WI-103 security tests
│
└── docs/
    └── issues/
        ├── WI-101-bug-lectura-negativa.md
        ├── WI-102-perf-listado-medidores.md
        └── WI-103-security-endpoint-admin.md

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Verifying the demo

After Fixi has resolved all 3 work items, you should be able to:

• See 3 PRs in this repo, one per work item, each with a clean diff
• Run dotnet test and see 8 passed, 0 failed
• Read the conventional commits in git log (fix:, perf:, fix: for security)
• Check that master was never touched directly — every change is on a fix/, perf/, or security/ branch

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License

Proprietary — Lots of Context LLC · 2026