SPFKTesting

A Swift package providing shared test resources and utilities for all SPFK test targets. Bundles a catalog of audio, video and image files used across the SPFK ecosystem, resolved against either bundle layout SwiftPM produces.

Overview

SPFKTesting provides two main components:

• TestBundleResources — A Sendable singleton exposing 60+ named audio, video and image test files organized into collections by purpose (format coverage, metadata markers, edge cases).
• Tag extensions — Custom Swift Testing tags (development, file, automation, realtime, engine) for categorizing tests across SPFK modules.

Key Types

TestBundleResources

Singleton providing typed access to bundled test resources. Used by downstream packages for audio format testing, metadata parsing, and file I/O validation.

let resources = TestBundleResources.shared

// Access individual files
let wav = resources.tabla_wav
let mp3 = resources.mp3_id3

// Iterate format collections
for url in resources.formats {
    // tabla.aac, tabla.aif, tabla.caf, tabla.flac,
    // tabla.m4a, tabla.mp3, tabla.mp4, tabla.wav (+ tabla.ogg on macOS)
}

for url in resources.markerFormats {
    // Formats supporting RIFF/Chapter markers and metadata
}

for url in resources.audioCases {
    // Diverse set for broad audio testing
}

formats and markerFormats are the AVFoundation-openable series. The Matroska members of the tabla series are deliberately outside both, since nothing in AVFoundation can open them — reach them by name (tabla_mka, tabla_flac_mka, tabla_pcm_mka).

BundleResources

Generic resource resolver that maps file names to URLs within a bundle.

The two bundle layouts are a build-system difference, not a platform one. Xcode writes Contents/Resources; SwiftPM's CLI build writes the resources flat at the bundle root. Both occur on macOS, so resourcesDirectory asks Bundle for its own resourceURL rather than appending a path, and a fixture resolves under xcodebuild and swift test alike.

let br = BundleResources(bundleURL: Bundle.module.bundleURL)
let url = br.resource(named: "tabla.wav")

Test Tags

Custom tags for filtering test execution in Swift Testing test plans:

@Test(.tags(.file))
func readWavMetadata() { ... }

@Test(.tags(.realtime))
func displayLinkTiming() { ... }

Bundled Resources

Audio (30 files, plus keys/ and rated/)

The tabla series is same-audio-different-format — every member is the same performance, so a test can assert one against another. Two caveats live in the series itself: tabla.aac and tabla.m4a carry encoder priming the container does not declare, so they are offset from the rest, while tabla_flac.mka and tabla_pcm.mka are sample-exact against tabla.wav.

Resource	Purpose
tabla.* (10 formats)	Format coverage: AAC, AIF, CAF, FLAC, M4A, MKA, MP3, MP4, OGG, WAV
tabla_flac.mka	FLAC in Matroska — lossless, sample-exact against tabla.wav
tabla_pcm.mka	24-bit PCM in Matroska — no converter in the decode path
tabla_6_channel.wav	Multi-channel audio
tabla_legacy_picture.flac	Legacy XiphComment METADATA_BLOCK_PICTURE artwork
and-oh-how-they-danced.mp3	ID3 metadata
and-oh-how-they-danced.wav	BEXT v2 metadata
and-oh-how-they-danced_2.wav	BEXT v2 variant
123456789_60BPM_48k.wav	BEXT v1, tempo reference
ITUNSMPB.m4a	iTunes gapless priming atom
cowbell.wav	General audio
cowbell_bext.wav	BEXT metadata
pink_noise.wav	Signal processing reference
no metadata.mp3	No metadata edge case
xmp.mp3	XMP metadata
toc_many_children.mp3	Complex TOC structure
no_data_chunk.wav	Missing data chunk edge case
ixml.wav	Full iXML specification
bext_ixml_external.flac	BEXT and iXML in FLAC APPLICATION blocks
boom.addAudio	Custom extension (M4A internally)
keys/ (12 files)	Musical key detection reference, one per chromatic root
rated/ (6 files)	80/100 star rating across WAV, MP3, FLAC, M4A, OGG, AIF

Video (6 files)

Matroska is absent from AVURLAsset.audiovisualTypes(), so these exist to exercise the demuxer in spfk-matroska — which is also why an audio-only .mov is not a substitute for sample.mov.

Resource	Purpose
sample.mov	A complete 6 KB QuickTime movie — a real container with a video track
sample.mkv	H.264 + AAC in Matroska
sample.webm	VP9 + Opus — no avcC, so it catches code assuming every track has codec private data
sample.mka	Matroska audio with no video track
sample-nested-seekhead.mkv	SeekHead pointing at a second SeekHead
sample-interleaved-cues.mkv	Cues indexing only the video track, as most muxers write them

Images (4 files)

Resource	Purpose
sharksandwich.jpg	Image metadata testing
sharksandwich.heic	HEIC read path
sharksandwich.webp	WebP — readable but not writable, so artwork transcodes to JPEG
songbird.jpg	Second image, for collection and comparison tests

Usage

Add SPFKTesting as a dependency in your test target only:

.testTarget(
    name: "MyPackageTests",
    dependencies: ["SPFKTesting"]
)

Requirements

• Platforms: macOS 13+
• Swift: 6.2+

About

Spongefork is the personal software projects of musician and developer Ryan Francesconi. Dedicated to creative sound manipulation, his first application, Spongefork, was released in 1999 for macOS 8. From 2026, Spongefork returns as his software container for more musical experimentation. In addition to software releases, open source components can be found on his GitHub page.