# TeslaConsole.DiffTests — differential equivalence suite

Verifies that the **reconstructed** `TeslaConsole.exe` (built from the decompiled
source in this repo) behaves identically to the **original** reference binary in
[`original/TeslaConsole.exe`](../../original/TeslaConsole.exe).

## How it works

Both files carry the *exact same* assembly identity
(`TeslaConsole, Version=4.11.3.37076`), so the .NET loader will not hold both in
one AppDomain. The suite therefore loads each assembly into its **own child
AppDomain** (`DifferentialFixture`) and drives it through a `MarshalByRefObject`
proxy (`Invoker`). This is why the project targets **net48** — AppDomains are a
.NET Framework feature.

Each child domain is given a probe directory (the recovered build's output, which
ships every dependency DLL) so the original — which is distributed without its
proprietary dependencies — still resolves its references for metadata inspection.

### What is compared

1. **Public API surface** (`PublicApiSurfaceTests`)
   Every public type and public member (signature-for-signature) exposed by the
   original must also be exposed by the recovered build. Compiler-generated members
   and property/event accessor methods are excluded — the README at the repo root
   notes those legitimately differ between a decompilation and the lost sources.

2. **Behavioral output** (`BehavioralEquivalenceTests`)
   The same deterministic, dependency-free methods are invoked in *both* assemblies
   over a battery of inputs and the results must match byte-for-byte:
   - `RPStrings.GetTimeString` (mm:ss formatting + 0.5 s rounding)
   - `HostTypeHelper.Parse(...).ToString()` (incl. invalid-input exceptions)
   - `PlasmaBitmaps.ConvertBitmap` (1-bpp packing of a known pixel pattern)
   - `PlasmaBitmaps.GenerateString` (full GDI text → 1-bpp plasma pipeline)
   - `RPMap` / `RPVehicle` XML parsing
   - `SiteManagement` well-known application GUID constants
   - `Tuple.Create<,>` generic factory

   A negative-control test (`Harness_Distinguishes_Different_Outputs`) proves the
   harness can actually see a difference, so a green run is never vacuous.

## Running

```
dotnet test tests/TeslaConsole.DiffTests/TeslaConsole.DiffTests.csproj
```

A project reference builds the reconstruction first, and the suite always tests
the most recently built `bin/{Debug,Release}/net48/TeslaConsole.exe`.

## Scope / limitations

This compares **deterministic logic**. It deliberately does not drive the WinForms
UI, the pod networking, secure-configuration, or hardware-facing code — those
require the live console, its pods, and the proprietary services, and are not
reproducible in a unit test. The API-surface test still asserts those types exist
with matching signatures even though their behavior isn't exercised.