chore(carv2): add fixtures and test expectations from go-car

.gitignore

@@ -4,4 +4,5 @@ node_modules/
 coverage/
 build/
 dist/
-types/
+types/
+examples/node_modules/

.npmignore

@@ -0,0 +1,12 @@
+test/fixtures/
+test/fixtures.js
+test/fixtures-expectations.js
+esm/browser-test/fixtures.js
+esm/node-test/fixtures.js
+cjs/browser-test/fixtures.js
+cjs/node-test/fixtures.js
+test/fixtures-expectations.js
+esm/browser-test/fixtures-expectations.js
+esm/node-test/fixtures-expectations.js
+cjs/browser-test/fixtures-expectations.js
+cjs/node-test/fixtures-expectations.js

lib/decoder.js

@@ -29,6 +29,9 @@ const V2_HEADER_LENGTH = /* characteristics */ 16 /* v1 offset */ + 8 /* v1 size
  */
 async function readVarint (reader) {
   const bytes = await reader.upTo(8)
+  if (!bytes.length) {
+    throw new Error('Unexpected end of data')
+  }
   const i = varint.decode(bytes)
   reader.seek(varint.decode.bytes)
   return i
@@ -92,7 +95,7 @@ export async function readHeader (reader, strictVersion) {
   }
   // version 2
   const v2Header = await readV2Header(reader)
-  reader.seek(reader.pos - v2Header.dataOffset)
+  reader.seek(v2Header.dataOffset - reader.pos)
   const v1Header = await readHeader(reader, 1)
   return Object.assign(v1Header, v2Header)
   /* c8 ignore next 2 */

package.json

@@ -9,7 +9,7 @@
     "lint": "standard",
     "build": "npm run build:js && npm run build:types",
     "build:js": "ipjs build --tests --main && npm run build:copy",
-    "build:copy": "mkdir -p dist/examples/ && cp -a tsconfig.json *.js *.ts lib test dist/ && cp examples/*.* dist/examples/",
+    "build:copy": "mkdir -p dist/examples/ && cp -a tsconfig.json .npmignore *.js *.ts lib test dist/ && cp examples/*.* dist/examples/ && rm -rf dist/test/fixtures/",
     "build:types": "tsc --build && mv types dist",
     "test:cjs": "rm -rf dist && npm run build && cp test/go.car dist/cjs/node-test/ && mocha dist/cjs/node-test/test-*.js && mocha dist/cjs/node-test/node-test-*.js && npm run test:cjs:browser",
     "test:esm": "rm -rf dist && npm run build && cp test/go.car dist/esm/node-test/ && mocha dist/esm/node-test/test-*.js && mocha dist/esm/node-test/node-test-*.js && npm run test:esm:browser",
@@ -211,4 +211,4 @@
       "@semantic-release/git"
     ]
   }
-}
+}

test/_fixtures_to_js.mjs

@@ -0,0 +1,24 @@
+#!/usr/bin/env node
+
+import { readdir, readFile, writeFile } from 'fs/promises'
+import { dirname, join } from 'path'
+
+async function main () {
+  const thisdir = dirname(new URL(import.meta.url).pathname)
+  const outfile = join(thisdir, 'fixtures.js')
+  const fixturesdir = join(thisdir, 'fixtures')
+  const files = await readdir(fixturesdir)
+  let content = '/** @type {Record<string, string>} */\nexport const data = {\n'
+  for (const f of files) {
+    content += `  '${f}': '`
+    content += (await readFile(join(fixturesdir, f))).toString('base64')
+    content += '\',\n'
+  }
+  content += '  _: \'\'\n}\n'
+  await writeFile(join(outfile), content, 'utf8')
+}
+
+main().catch((err) => {
+  console.error(err)
+  process.exit(1)
+})

test/fixtures/sample-corrupt-pragma.car

@@ -0,0 +1 @@
+�eroots�gversio

test/fixtures/sample-rootless-v42.car

@@ -0,0 +1 @@
+�gversion*

test/test-reader.js

@@ -2,9 +2,11 @@
 
 import { CarReader } from '@ipld/car/reader'
 import { CarWriter } from '@ipld/car/writer'
+import { bytesReader, readHeader } from '@ipld/car/decoder'
 import * as Block from 'multiformats/block'
 import { sha256 } from 'multiformats/hashes/sha2'
 import * as raw from 'multiformats/codecs/raw'
+import { base64 } from 'multiformats/bases/base64'
 import * as dagPb from '@ipld/dag-pb'
 import {
   carBytes,
@@ -22,6 +24,8 @@ import {
   verifyBlocks,
   verifyCids
 } from './verify-store-reader.js'
+import { data as fixtures } from './fixtures.js'
+import { expectations as fixtureExpectations } from './fixtures-expectations.js'
 
 describe('CarReader fromBytes()', () => {
   it('complete', async () => {
@@ -195,3 +199,47 @@ describe('CarReader fromIterable()', () => {
     })
   })
 })
+
+describe('Shared fixtures', () => {
+  describe('Header', () => {
+    for (const [name, { version: expectedVersion, err: expectedError }] of Object.entries(fixtureExpectations)) {
+      it(name, async () => {
+        const data = base64.baseDecode(fixtures[name])
+        let header
+        try {
+          header = await readHeader(bytesReader(data))
+        } catch (err) {
+          if (expectedError != null) {
+            assert.equal(err.message, expectedError)
+            return
+          }
+          assert.ifError(err)
+        }
+        if (expectedError != null) {
+          assert.fail(`Expected error: ${expectedError}`)
+        }
+        assert.isDefined(header, 'did not decode header')
+        if (expectedVersion != null && header != null) {
+          assert.strictEqual(header.version, expectedVersion)
+        }
+      })
+    }
+  })
+
+  describe('Contents', () => {
+    for (const [name, { cids: expectedCids }] of Object.entries(fixtureExpectations)) {
+      if (expectedCids == null) {
+        continue
+      }
+      it(name, async () => {
+        const data = base64.baseDecode(fixtures[name])
+        const reader = await CarReader.fromBytes(data)
+        let i = 0
+        for await (const cid of reader.cids()) {
+          assert.strictEqual(cid.toString(), expectedCids[i++])
+        }
+        assert.strictEqual(i, expectedCids.length)
+      })
+    }
+  })
+})

tsconfig.json

@@ -34,7 +34,8 @@
       "@ipld/car/reader": [ "./lib/reader.js" ],
       "@ipld/car/indexed-reader": [ "./lib/indexed-reader.js" ],
       "@ipld/car/iterator": [ "./lib/iterator.js" ],
-      "@ipld/car/indexer": [ "./lib/indexer.js" ]
+      "@ipld/car/indexer": [ "./lib/indexer.js" ],
+      "@ipld/car/decoder": [ "./lib/decoder.js" ],
     }
   },
   "exclude": [