Testable Requirements - New Streams API

This document lists all testable requirements for the new streams API implementation.

Legend

• ✅ Covered by existing tests
• ⚠️ Partially covered
• ❌ Not covered

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1. Stream.push()

Creates a bonded writer and async iterable pair for push-based streaming.

1.1 Basic Operation

ID	Requirement	Status
PUSH-001	Returns object with writer and readable properties	✅
PUSH-002	Writer.write() accepts string (UTF-8 encoded)	✅
PUSH-003	Writer.write() accepts Uint8Array	✅
PUSH-004	Writer.writev() writes multiple chunks atomically	✅
PUSH-005	Writer.writeSync() returns boolean (true if accepted)	✅
PUSH-006	Writer.writevSync() returns boolean (true if accepted)	✅
PUSH-007	Writer.end() signals end of stream	✅
PUSH-008	Writer.end() returns total bytes written	✅
PUSH-009	Writer.endSync() returns total bytes written	✅
PUSH-010	Writer.fail() signals error to consumer	✅
PUSH-011	Writer.failSync() signals error synchronously	✅
PUSH-012	Readable yields Uint8Array[] batches	✅

1.2 Backpressure - desiredSize

ID	Requirement	Status
PUSH-020	desiredSize reflects available buffer space	✅
PUSH-021	desiredSize is 0 when buffer is full	✅
PUSH-022	desiredSize is null after close	✅
PUSH-023	desiredSize is null after fail	✅
PUSH-024	desiredSize is always >= 0 (never negative)	✅

1.3 Backpressure - highWaterMark

ID	Requirement	Status
PUSH-030	Default highWaterMark is 4	✅
PUSH-031	Custom highWaterMark is respected	✅
PUSH-032	highWaterMark is clamped to [1, implementation-defined max (>= 1024)]	✅
PUSH-033	writev counts as single slot for backpressure	✅

1.4 Backpressure Policies

ID	Requirement	Status
PUSH-040	backpressure: 'strict' rejects async writes when buffer full	✅
PUSH-041	backpressure: 'strict' returns false for sync writes when buffer full	✅
PUSH-042	backpressure: 'block' waits for space on async writes	✅
PUSH-043	backpressure: 'block' returns false for sync writes when buffer full	✅
PUSH-044	backpressure: 'drop-oldest' discards oldest buffered data	✅
PUSH-045	backpressure: 'drop-newest' discards incoming data when buffer full	✅

1.5 Consumer Termination

ID	Requirement	Status
PUSH-050	Consumer break closes writer (desiredSize becomes null)	✅
PUSH-051	writeSync returns false after consumer terminates	✅
PUSH-052	iterator.throw() propagates error to writer	✅

1.6 AbortSignal

ID	Requirement	Status
PUSH-060	signal option aborts stream when signaled	✅
PUSH-061	Already-aborted signal creates errored stream	✅
PUSH-062	Write blocked on backpressure rejects on signal abort	��

1.7 Transforms

ID	Requirement	Status
PUSH-070	Accepts transforms as arguments	✅
PUSH-071	Multiple transforms are applied in order	✅
PUSH-072	Transforms are applied lazily (on pull)	✅

1.8 Edge Cases

ID	Requirement	Status
PUSH-080	Handles empty writes	✅
PUSH-081	Reading from already-closed stream returns done	✅
PUSH-082	Second end() call rejects with TypeError	✅
PUSH-083	Batches synchronously available chunks	✅
PUSH-084	Handles concurrent writes and reads	✅

1.9 Drainable Protocol

ID	Requirement	Status
PUSH-090	Writer implements drainable protocol	✅
PUSH-091	ondrain returns resolved Promise when desiredSize > 0	✅
PUSH-092	ondrain returns null when desiredSize is null (writer closed)	✅
PUSH-093	ondrain returns null when desiredSize is null (writer failed)	✅
PUSH-094	ondrain returns pending Promise when desiredSize === 0	✅
PUSH-095	ondrain Promise resolves with false when writer closes while waiting	✅
PUSH-096	ondrain Promise rejects when writer fails while waiting	✅
PUSH-097	Multiple drain waiters all resolve together	✅
PUSH-098	ondrain returns null for non-drainable objects	✅
PUSH-099	ondrain works with event source pattern	✅

---

2. Stream.from() / Stream.fromSync()

Creates iterables from various input sources.

2.1 ByteInput Handling

ID	Requirement	Status
FROM-001	from() handles string input (UTF-8 encoded)	✅
FROM-002	from() handles Uint8Array input	✅
FROM-003	from() handles ArrayBuffer input	✅
FROM-004	fromSync() handles string input	✅
FROM-005	fromSync() handles Uint8Array input	✅
FROM-006	fromSync() handles ArrayBuffer input	✅
FROM-007	fromSync() handles ArrayBufferView (Int8Array, DataView)	✅

2.2 Iterable Handling

ID	Requirement	Status
FROM-010	from() handles async generator	✅
FROM-011	from() handles sync generator	✅
FROM-012	from() handles array input	✅
FROM-013	fromSync() handles sync generator	✅
FROM-014	fromSync() handles array input	✅
FROM-015	from() flattens nested async iterables	✅
FROM-016	fromSync() flattens nested iterables	✅
FROM-017	fromSync() flattens arrays yielded by generators	✅

2.3 Protocol Handling

ID	Requirement	Status
FROM-020	from() handles toAsyncStreamable returning promise	✅
FROM-021	from() handles toAsyncStreamable returning async iterable	✅
FROM-022	from() prefers toAsyncStreamable over toStreamable	✅
FROM-023	from() falls back to toStreamable when toAsyncStreamable absent	✅
FROM-024	fromSync() handles toStreamable returning string	✅
FROM-025	fromSync() handles toStreamable returning array	✅
FROM-026	fromSync() handles nested ToStreamable objects	✅

2.4 String Coercion Fallback

ID	Requirement	Status
FROM-030	fromSync() handles URL (custom toString)	✅
FROM-031	fromSync() handles Date (custom toString)	✅
FROM-032	fromSync() handles objects with custom toString	✅

2.5 Error Handling

ID	Requirement	Status
FROM-040	fromSync() rejects plain objects without custom toString	✅
FROM-041	fromSync() rejects null	✅
FROM-042	fromSync() rejects undefined	✅
FROM-043	fromSync() rejects numbers	✅
FROM-044	from() rejects non-iterable input	✅
FROM-045	from() propagates errors from async generators	✅

2.6 Empty Inputs

ID	Requirement	Status
FROM-050	from() handles empty string	✅
FROM-051	from() handles empty async generator	✅
FROM-052	fromSync() handles empty string	✅
FROM-053	fromSync() handles empty generator	✅
FROM-054	fromSync() handles empty array	✅

---

3. Stream.pull() / Stream.pullSync()

Creates pull-through pipelines with transforms.

3.1 Basic Operation

ID	Requirement	Status
PULL-001	pull() passes through source without transforms	✅
PULL-002	pull() works with sync source	✅
PULL-003	pullSync() passes through source without transforms	✅
PULL-004	pull() applies single transform	✅
PULL-005	pull() chains multiple transforms in order	✅
PULL-006	pullSync() applies single transform	✅
PULL-007	pullSync() chains multiple transforms	✅

3.2 Transform Output Types

ID	Requirement	Status
PULL-010	Transform returning Uint8Array[] is passed through	✅
PULL-011	Transform returning string is UTF-8 encoded	✅
PULL-012	Transform returning nested iterables is flattened	✅
PULL-013	Transform returning null filters out batch	✅

3.3 Async Transforms

ID	Requirement	Status
PULL-020	Handles async transform function	✅
PULL-021	Handles transform returning Promise	✅
PULL-022	Handles transform returning async generator	✅

3.4 Stateful Transforms

ID	Requirement	Status
PULL-030	Supports stateful transform object	✅
PULL-031	Receives null flush signal at end	✅
PULL-032	Pipeline signal fires on transforms when error occurs	✅

3.5 Options

ID	Requirement	Status
PULL-040	Accepts options as last argument	✅
PULL-041	Respects AbortSignal	✅
PULL-042	Handles already-aborted signal	✅

---

4. Stream.pipeTo() / Stream.pipeToSync()

Consumes source and writes to a writer with optional transforms.

4.1 Basic Operation

ID	Requirement	Status
PIPE-001	pipeTo() writes source to writer without transforms	✅
PIPE-002	pipeTo() works with sync source	✅
PIPE-003	pipeTo() applies transforms before writing	✅
PIPE-004	pipeToSync() writes source to writer without transforms	✅
PIPE-005	pipeToSync() applies transforms before writing	✅

4.2 Options

ID	Requirement	Status
WRITE-010	preventClose keeps writer open on completion	✅
WRITE-011	preventFail keeps writer from failing on error	✅
WRITE-012	Respects AbortSignal	✅

4.3 Error Handling

ID	Requirement	Status
WRITE-020	Fails writer on source error	✅
WRITE-021	Throws if no writer provided	✅
WRITE-025	pipeTo passes signal to writer.write()	✅
WRITE-026	pipeTo passes signal to writer.end()	✅

4.4 Special Cases

ID	Requirement	Status
WRITE-030	Handles writer that is also a transform	✅

---

5. Consumer Functions

Terminal consumers that collect streams into memory.

5.1 Stream.bytes() / Stream.bytesSync()

ID	Requirement	Status
BYTES-001	bytes() collects all bytes from async source	✅
BYTES-002	bytes() collects all bytes from sync source	✅
BYTES-003	bytesSync() collects all bytes from source	✅
BYTES-004	bytesSync() handles multiple chunks	✅
BYTES-005	bytesSync() handles empty source	✅
BYTES-006	bytes() respects AbortSignal	✅
BYTES-007	bytes() respects byte limit	✅
BYTES-008	bytesSync() respects byte limit	✅
BYTES-009	bytesSync() allows data within limit	✅

5.2 Stream.text() / Stream.textSync()

ID	Requirement	Status
TEXT-001	text() decodes UTF-8 by default	✅
TEXT-002	text() handles multi-byte UTF-8 characters	✅
TEXT-003	text() respects AbortSignal	✅
TEXT-004	textSync() decodes UTF-8 by default	✅
TEXT-005	textSync() handles multi-byte UTF-8 characters	✅
TEXT-006	textSync() respects encoding option	✅
TEXT-007	textSync() throws on invalid UTF-8 (fatal mode)	✅
TEXT-008	textSync() respects byte limit	✅

5.3 Stream.arrayBuffer() / Stream.arrayBufferSync()

ID	Requirement	Status
ARRAYBUF-001	arrayBuffer() returns ArrayBuffer	✅
ARRAYBUF-002	arrayBuffer() respects AbortSignal	✅
ARRAYBUF-003	arrayBufferSync() returns ArrayBuffer	✅
ARRAYBUF-004	arrayBufferSync() respects byte limit	✅

5.4 Stream.array() / Stream.arraySync()

ID	Requirement	Status
ARRAY-001	array() collects all chunks from async source	✅
ARRAY-002	array() collects all chunks from sync source	✅
ARRAY-003	arraySync() collects all chunks from source	✅
ARRAY-004	arraySync() handles single chunk	✅
ARRAY-005	arraySync() handles empty source	✅
ARRAY-006	arraySync() respects byte limit	✅
ARRAY-007	arraySync() allows data within limit	✅
ARRAY-008	array() respects AbortSignal	✅
ARRAY-009	array() respects byte limit	✅
ARRAY-010	array() preserves chunk boundaries	✅

---

6. Stream.broadcast()

Push-model multi-consumer streaming.

6.1 Basic Operation

ID	Requirement	Status
BCAST-001	Creates writer and broadcast pair	✅
BCAST-002	Single consumer receives data	✅
BCAST-003	Multiple consumers receive same data	✅
BCAST-004	Tracks consumer count	✅
BCAST-005	Late subscribers receive new data	✅

6.2 Buffer Management

ID	Requirement	Status
BCAST-010	Respects buffer limit	✅
BCAST-011	Trims buffer as consumers advance	✅
BCAST-012	Uses drop-oldest policy	✅
BCAST-013	Uses drop-newest policy	✅

6.3 Writer Operations

ID	Requirement	Status
BCAST-020	Tracks total bytes written	✅
BCAST-021	Supports writev	✅
BCAST-022	Propagates errors via fail	✅

6.4 Cancel

ID	Requirement	Status
BCAST-030	cancel() cancels all consumers without error	✅
BCAST-031	cancel(reason) cancels all consumers with error	✅
BCAST-032	cancel() is idempotent	✅

6.5 Symbol.dispose

ID	Requirement	Status
BCAST-040	Symbol.dispose cancels broadcast	✅

6.6 AbortSignal

ID	Requirement	Status
BCAST-050	Respects already-aborted signal	✅
BCAST-051	Cancels on signal abort	✅

6.7 Transforms

ID	Requirement	Status
BCAST-070	Applies single transform to consumer	✅
BCAST-071	Applies multiple transforms in order	✅
BCAST-072	Allows different transforms per consumer	✅

6.9 Drainable Protocol

ID	Requirement	Status
BCAST-080	Writer implements drainable protocol	✅
BCAST-081	ondrain returns resolved Promise when desiredSize > 0	✅
BCAST-082	ondrain returns null when desiredSize is null (writer closed)	✅
BCAST-083	ondrain returns null when desiredSize is null (writer failed)	✅
BCAST-084	ondrain returns pending Promise when desiredSize === 0	✅
BCAST-085	ondrain Promise resolves with false when writer closes while waiting	✅
BCAST-086	ondrain Promise rejects when writer fails while waiting	✅
BCAST-087	Multiple drain waiters all resolve together	✅

---

7. Stream.share() / Stream.shareSync()

Pull-model multi-consumer streaming.

7.1 Basic Operation

ID	Requirement	Status
SHARE-001	share() creates a share instance	✅
SHARE-002	share() allows single consumer to pull data	✅
SHARE-003	share() allows multiple consumers to share data	✅
SHARE-004	share() handles sync source	✅
SHARE-005	shareSync() creates a sync share instance	✅
SHARE-006	shareSync() allows single consumer to pull data	✅
SHARE-007	shareSync() allows interleaved iteration of multiple consumers	✅

7.2 Buffer Management

ID	Requirement	Status
SHARE-010	Buffers data for slow consumers	✅
SHARE-011	share() respects buffer limit with strict policy (throws)	✅
SHARE-012	share() drops oldest with drop-oldest policy	✅
SHARE-013	shareSync() throws on buffer overflow with strict policy	✅
SHARE-014	shareSync() drops oldest with drop-oldest policy	✅

7.3 Cancel

ID	Requirement	Status
SHARE-020	share() cancel() cancels all consumers without error	✅
SHARE-021	share() cancel(reason) cancels all consumers with error	✅
SHARE-022	share() cancel() closes source iterator	✅
SHARE-023	shareSync() cancel() cancels all consumers	✅

7.4 Symbol.dispose

ID	Requirement	Status
SHARE-030	Symbol.dispose cancels share	✅

7.5 AbortSignal

ID	Requirement	Status
SHARE-040	Respects already-aborted signal	✅

7.6 Error Propagation

ID	Requirement	Status
SHARE-050	Propagates source errors to all consumers	✅

7.7 Transforms

ID	Requirement	Status
SHARE-070	share() applies single transform to consumer	✅
SHARE-071	share() applies multiple transforms in order	✅
SHARE-072	share() allows different transforms per consumer	✅
SHARE-073	share() supports transforms with options	✅
SHARE-074	shareSync() applies single transform to sync consumer	✅

---

8. Stream.duplex()

Creates a pair of connected duplex channels for bidirectional communication.

8.1 Basic Operation

ID	Requirement	Status
DUPLEX-001	Returns tuple of two DuplexChannel instances	✅
DUPLEX-002	Data written to A appears in B's readable	✅
DUPLEX-003	Data written to B appears in A's readable	✅
DUPLEX-004	Bidirectional communication works	✅

8.2 Close Behavior

ID	Requirement	Status
DUPLEX-005	close() is idempotent	✅
DUPLEX-006	Symbol.asyncDispose works	✅
DUPLEX-007	Closing one channel doesn't affect the other direction	✅

8.3 Options

ID	Requirement	Status
DUPLEX-008	Respects highWaterMark option	✅
DUPLEX-009	Respects backpressure option	✅
DUPLEX-010	Respects AbortSignal option	✅
DUPLEX-013	Respects per-direction options	✅
DUPLEX-014	Per-direction options override shared options	✅

8.4 Real-World Patterns

ID	Requirement	Status
DUPLEX-011	Supports request-response pattern	✅
DUPLEX-012	Supports multiple message exchanges	✅

---

9. Stream.merge()

Merges multiple async sources by temporal order.

ID	Requirement	Status
MERGE-001	Handles empty sources	✅
MERGE-002	Handles single source	✅
MERGE-003	Merges multiple sources	✅
MERGE-004	Yields in temporal order (first-come)	✅
MERGE-005	Respects AbortSignal	✅
MERGE-006	Handles source errors	✅
MERGE-007	Accepts options as last argument	✅

---

10. Stream.tap() / Stream.tapSync()

Creates pass-through transforms for observation.

ID	Requirement	Status
TAP-001	tap() calls callback with chunks	✅
TAP-002	tap() supports async callback	✅
TAP-003	tapSync() calls callback with chunks	✅
TAP-004	tapSync() passes chunks through unchanged	✅

---

11. Protocol Symbols

Symbols for custom type integration.

ID	Requirement	Status
PROTO-001	toStreamable symbol allows sync conversion	✅
PROTO-002	toAsyncStreamable symbol allows async conversion	✅
PROTO-003	broadcastProtocol symbol allows custom broadcast	✅
PROTO-004	shareProtocol symbol allows custom share	✅
PROTO-005	shareSyncProtocol symbol allows custom sync share	✅
PROTO-006	drainableProtocol symbol allows drain notification	✅

---

Summary Statistics

Category	Total	Covered
Stream.push()	46	45
Stream.from() / fromSync()	26	26
Stream.pull() / pullSync()	17	17
Stream.pipeTo() / pipeToSync()	12	10
Consumer Functions	27	27
Stream.broadcast()	26	26
Stream.share() / shareSync()	22	22
Stream.duplex()	14	14
Stream.merge()	7	7
Stream.tap() / tapSync()	4	4
Protocol Symbols	6	6
Total	207	207

Coverage: 100% of specified requirements are tested.