Consistent KISS naming and tests

src/kiss.ts

@@ -6,14 +6,14 @@ export const KISS_FESC = 0xdb;
 export const KISS_TFEND = 0xdc;
 export const KISS_TFESC = 0xdd;
 
-export type KissFrame = {
+export type KISSFrame = {
   port: number; // 0-15
   command: number; // 0 = data, 1 = TX delay, etc.
   data: Uint8Array;
 };
 
 // Encode a KISS frame (data only, port 0 by default)
-export function encodeKissFrame(data: Uint8Array, port = 0, command = 0): Uint8Array {
+export function encodeKISSFrame(data: Uint8Array, port = 0, command = 0): Uint8Array {
   const out: number[] = [KISS_FEND];
   // Command byte: upper 4 bits = port, lower 4 bits = command
   out.push(((port & 0x0f) << 4) | (command & 0x0f));
@@ -31,7 +31,7 @@ export function encodeKissFrame(data: Uint8Array, port = 0, command = 0): Uint8A
 }
 
 // Decode a KISS frame (returns null if not a valid frame)
-export function decodeKissFrame(buf: Uint8Array): KissFrame | null {
+export function decodeKISSFrame(buf: Uint8Array): KISSFrame | null {
   if (buf.length < 3 || buf[0] !== KISS_FEND || buf[buf.length - 1] !== KISS_FEND) return null;
   let i = 1;
   const cmd = buf[i++];
@@ -53,14 +53,14 @@ export function decodeKissFrame(buf: Uint8Array): KissFrame | null {
 }
 
 // Async generator to extract KISS frames from a stream of bytes
-export async function* kissFrameReader(source: AsyncIterable<Uint8Array>): AsyncGenerator<KissFrame> {
+export async function* kissFrameReader(source: AsyncIterable<Uint8Array>): AsyncGenerator<KISSFrame> {
   let buffer: number[] = [];
   let inFrame = false;
   for await (const chunk of source) {
     for (const b of chunk) {
       if (b === KISS_FEND) {
         if (inFrame && buffer.length > 0) {
-          const frame = decodeKissFrame(Uint8Array.from([KISS_FEND, ...buffer, KISS_FEND]));
+          const frame = decodeKISSFrame(Uint8Array.from([KISS_FEND, ...buffer, KISS_FEND]));
           if (frame) yield frame;
         }
         buffer = [];
@@ -73,7 +73,7 @@ export async function* kissFrameReader(source: AsyncIterable<Uint8Array>): Async
 }
 
 // Write a KISS frame to a sink (e.g., serial port)
-export async function kissFrameWriter(sink: (data: Uint8Array) => Promise<void>, frame: KissFrame) {
-  const buf = encodeKissFrame(frame.data, frame.port, frame.command);
+export async function kissFrameWriter(sink: (data: Uint8Array) => Promise<void>, frame: KISSFrame) {
+  const buf = encodeKISSFrame(frame.data, frame.port, frame.command);
   await sink(buf);
 }

test/kiss.test.ts

@@ -0,0 +1,113 @@
+import { describe, it, expect } from "vitest";
+import {
+  KISS_FEND,
+  KISS_FESC,
+  KISS_TFEND,
+  KISS_TFESC,
+  encodeKISSFrame,
+  decodeKISSFrame,
+  kissFrameReader,
+  kissFrameWriter,
+  type KISSFrame,
+} from "../src/kiss";
+
+const u8 = (arr: number[]) => Uint8Array.from(arr);
+
+describe("kiss.ts", () => {
+  it("encodeKISSFrame produces proper FEND wrappers and decodes back", () => {
+    const data = u8([1, 2, 3]);
+    const buf = encodeKISSFrame(data);
+    expect(buf[0]).toBe(KISS_FEND);
+    expect(buf[buf.length - 1]).toBe(KISS_FEND);
+    const frame = decodeKISSFrame(buf);
+    expect(frame).not.toBeNull();
+    expect(frame!.port).toBe(0);
+    expect(frame!.command).toBe(0);
+    expect(Array.from(frame!.data)).toEqual(Array.from(data));
+  });
+
+  it("encodes and decodes escape sequences correctly", () => {
+    const data = u8([0x01, KISS_FEND, 0x02, KISS_FESC, 0x03]);
+    const encoded = encodeKISSFrame(data, 1, 2);
+    // command byte should encode port=1, command=2
+    expect(encoded[1]).toBe(((1 & 0x0f) << 4) | (2 & 0x0f));
+    // ensure escaped bytes present
+    const arr = Array.from(encoded);
+    // look for FESC TFEND and FESC TFESC sequences
+    const hasFescTfend = arr.includes(KISS_FESC) && arr.includes(KISS_TFEND);
+    const hasFescTfesc = arr.includes(KISS_FESC) && arr.includes(KISS_TFESC);
+    expect(hasFescTfend).toBeTruthy();
+    expect(hasFescTfesc).toBeTruthy();
+
+    const decoded = decodeKISSFrame(encoded)!;
+    expect(decoded.port).toBe(1);
+    expect(decoded.command).toBe(2);
+    expect(Array.from(decoded.data)).toEqual(Array.from(data));
+  });
+
+  it("decodeKISSFrame returns null for invalid frames", () => {
+    // missing FEND start
+    expect(decodeKISSFrame(u8([0x00, 0x00, 0x00]))).toBeNull();
+
+    // invalid escape sequence
+    const bad = u8([KISS_FEND, 0x00, KISS_FESC, 0x00, KISS_FEND]);
+    expect(decodeKISSFrame(bad)).toBeNull();
+  });
+
+  it("parses port and command from the command byte", () => {
+    const port = 3;
+    const command = 4;
+    const data = u8([9, 8]);
+    const cmd = ((port & 0x0f) << 4) | (command & 0x0f);
+    const buf = u8([KISS_FEND, cmd, ...Array.from(data), KISS_FEND]);
+    const f = decodeKISSFrame(buf)!;
+    expect(f.port).toBe(port);
+    expect(f.command).toBe(command);
+    expect(Array.from(f.data)).toEqual(Array.from(data));
+  });
+
+  it("kissFrameReader yields frames assembled across chunks and ignores incomplete frames", async () => {
+    // create two frames and split them across chunks
+    const a = encodeKISSFrame(u8([1, 2, 3]));
+    const b = encodeKISSFrame(u8([4, 5]));
+
+    // craft an async iterable that yields multiple chunks, splitting frames
+    async function* source() {
+      // first chunk: first half of a
+      yield u8(Array.from(a.slice(0, 2)));
+      // second chunk: rest of a plus start of b
+      yield u8(Array.from(a.slice(2)).concat(Array.from(b.slice(0, 1))));
+      // third chunk: rest of b
+      yield u8(Array.from(b.slice(1)));
+    }
+
+    const results: KISSFrame[] = [];
+    for await (const fr of kissFrameReader(source())) {
+      results.push(fr);
+    }
+    expect(results.length).toBe(2);
+    expect(Array.from(results[0].data)).toEqual([1, 2, 3]);
+    expect(Array.from(results[1].data)).toEqual([4, 5]);
+
+    // incomplete frame (no trailing FEND) should not yield
+    async function* sourceIncomplete() {
+      const partial = Array.from(a.slice(0, a.length - 1));
+      yield u8(partial);
+    }
+    const got: KISSFrame[] = [];
+    for await (const fr of kissFrameReader(sourceIncomplete())) got.push(fr);
+    expect(got.length).toBe(0);
+  });
+
+  it("kissFrameWriter calls the sink with the encoded buffer", async () => {
+    const received: Uint8Array[] = [];
+    const sink = async (data: Uint8Array) => {
+      received.push(data);
+    };
+    const frame: KISSFrame = { port: 2, command: 1, data: u8([7, 8, 9]) };
+    await kissFrameWriter(sink, frame);
+    expect(received.length).toBe(1);
+    const expected = encodeKISSFrame(frame.data, frame.port, frame.command);
+    expect(Array.from(received[0])).toEqual(Array.from(expected));
+  });
+});