ersatztv/docs/testing.md

Testing map

Purpose: authoritative map of what each test project/suite covers and how to run it. Read this before adding tests, not just docs/contributing.md §8 (which now just points here).

Test projects

Project	Covers	Notes
ErsatzTV.Tests	API controllers + MediatR handlers	In-memory SQLite fixture: a shared SqliteConnection("Data Source=:memory:;Foreign Keys=False") kept open + EnsureCreatedAsync() (not full migration replay) + PRAGMA foreign_keys=OFF, then seed; a tiny IDbContextFactory wraps new TvContext(...). ~1,870 tests (approximate on purpose — an exact count goes stale on every PR that adds one; the previous hardcoded 828 was off by over a thousand).
ErsatzTV.Core.Tests	Domain logic, scheduling, IPTV/XMLTV generation	References ErsatzTV.Application directly — there is no separate Application.Tests project. ~650 tests + 1 skipped under TZ=UTC (the Block playout golden additionally skips under a non-UTC TZ; see Golden-file nets).
ErsatzTV.Scanner.Tests	Library scanning: scan handlers, folder scanners, NFO readers	Handler tests substitute the folder scanners + ILibraryRepository and assert the resulting repository writes (e.g. ScanLocalLibraryHandlerTests pins which LastScan levels a scan records — ersatztv#264). Fakes/Testably back the file-system-facing scanners. ~1,485 tests (approximate on purpose — an exact count goes stale on every PR that adds one). Additionally contains Core/FFmpeg/TranscodingTests — [Explicit] + [Combinatorial], so it never runs in CI or a plain dotnet test (it needs real ffmpeg/hardware) and contributes 0 to that count; run it by name when touching the transcoding pipeline.
ErsatzTV.Architecture.Tests	Layering rules via NetArchTest.eNhancedEdition	Core↛Infra/App/EF; FFmpeg↛all; App↛concrete providers. 5 tests. See docs/contributing.md §1.
ErsatzTV.FFmpeg.Tests	FFmpeg command construction	Build a pipeline, assert the exact rendered arg string (PipelineBuilderBaseTests.cs).
web/ (vitest)	React SPA unit tests	330 tests; run alongside typecheck + build (see below).

Golden-file nets

Three golden-file suites guard the highest-value, most-subtle output:

• M3U: ErsatzTV.Core.Tests/Iptv/ChannelPlaylistGoldenTests.cs (ersatztv#11) — env var ETV_UPDATE_GOLDENS
• XMLTV: ChannelGuideGoldenTests (ersatztv#28) — env var ETV_UPDATE_GOLDENS
• Playout build: ErsatzTV.Core.Tests/Scheduling/Goldens/PlayoutBuildGoldenTests.cs (ersatztv#163) — env var ETV_UPDATE_PLAYOUT_GOLDENS (deliberately separate from ETV_UPDATE_GOLDENS so regenerating one net can't silently rewrite the other). Snapshots the PlayoutItems each builder produces over a pinned build window. Covers the Classic (PlaybackOrder.Chronological), Block, and Sequential (YAML) builders. The Scripted end-to-end pipeline is excluded from this net — ScriptedPlayoutBuilder runs a user-authored external process that drives the engine over HTTP, which the in-memory harness can't pin; that integration harness is tracked in ersatztv#563. The scheduling behavior those scripts drive, though, lives in the in-process SchedulingEngine (the HTTP controller is a 1:1 pass-through) and IS directly testable — SchedulingEngineTests news it up with substitutes, and ContentEnumeratorBuilderTests (ersatztv#395) is the direct regression net over the enumerator-construction helper the Scripted and Sequential/YAML engines now share (decision: testing.scripted-playout-golden-deferred). The Sequential case (Sequential_yaml, ersatztv#381) builds from a committed YAML fixture (Goldens/Fixtures/sequential-schedule.yml) instead of a ProgramSchedule; it is TZ-independent (the count/all/duration handlers do UTC-only arithmetic — it passes, not skips, under a non-UTC TZ) so needs no Assume guard. A third case, Classic_clock_padded (ersatztv#77), locks clock-boundary padding: a FillerMode.Pad + PadToNearestMinute=15 PostRoll preset snaps content to :15, and the test both goldens the output and asserts every content item after the first starts on a quarter-hour. Its EPG counterpart is ErsatzTV.Core.Tests/Channels/ChannelGuideProjectorClockPadTests.cs (guide programmes stop on the padded boundary). The build reads no wall clock — time enters only via the caller-supplied start — so a pinned start is fully deterministic. Snapshots the raw PlayoutItem.Start/Finish (UTC), not the *Offset properties (those call .ToLocalTime() and would make the golden machine-TZ dependent). The Block case is TZ-sensitive by construction (BlockPlayoutBuilder maps template times via TimeZoneInfo.Local), so it is guarded with Assume.That(TimeZoneInfo.Local.BaseUtcOffset == Zero): it runs under TZ=UTC (CI) and reports inconclusive (a graceful skip, not a failure) under any other TZ. A real TZ seam for the block builder is ersatztv#380's scope.

All three locate their golden files via [CallerFilePath]. A missing golden is a hard fail, not a skip. Regenerate via ETV_UPDATE_GOLDENS=1 dotnet test ... (M3U/XMLTV) or ETV_UPDATE_PLAYOUT_GOLDENS=1 dotnet test ... (playout build).

Never set ETV_UPDATE_GOLDENS / ETV_UPDATE_PLAYOUT_GOLDENS in CI or from an agent. A golden diff during normal test runs means the code changed the output — regenerating to make the diff go away hides the change instead of surfacing it. Only a human who has confirmed the change is intentional should regenerate.

Timezone independence

The suite is timezone-independent (ersatztv#24). When constructing test PlayoutItems, always set a real Start (e.g. startState.CurrentTime.UtcDateTime) — never rely on the default DateTime.MinValue, which underflows DateTimeOffset.MinValue once a non-UTC local offset is applied (StartOffset calls ToLocalTime()). CI runs in UTC; local runs may not.

Running tests

Full .NET gate:

dotnet build ErsatzTV.sln
TZ=UTC dotnet test

CI adds --blame-hang-timeout 2m to catch hangs.

Fast subsets:

# single project
dotnet test ErsatzTV.Tests

# filtered
dotnet test ErsatzTV.Core.Tests --filter FullyQualifiedName~ChannelPlaylistGoldenTests

Web (web/):

npm test           # vitest
npm run typecheck  # tsc -b --pretty false
npm run lint       # eslint .
npm run build      # tsc -b && vite build

Per-PR verification gate

Before opening a PR: build the solution, run ErsatzTV.Tests + ErsatzTV.Core.Tests (plus ErsatzTV.Scanner.Tests, ErsatzTV.Architecture.Tests and ErsatzTV.FFmpeg.Tests if touched), and run the web test/lint/typecheck/build steps above. All must be green. A golden-file diff or an architecture-test failure is a hard stop — fix the code, don't regenerate/relax the test.

See also

• docs/ci-cd.md — CI pipeline (test → migrations → build), versioning, dependency management.
• docs/contributing.md §1 — layering rules enforced by ErsatzTV.Architecture.Tests.
• docs/contributing.md §8 — short pointer back to this doc.