test: add test for range request on multi block CAR (#55)

* test: add test for range request on multi block CAR

* fix: use proper range requested CAR file

* fix: test command

package.json

@@ -6,7 +6,7 @@
   "main": "src/index.js",
   "type": "module",
   "scripts": {
-    "test": "NODE_ENV=development TESTING=true node  --test test/",
+    "test": "NODE_ENV=development TESTING=true node  --test test/*",
     "build": "webpack --mode production",
     "prepack": "npm run build"
   },

test/car.spec.js

@@ -79,6 +79,23 @@ describe('CAR Verification', () => {
     assert.strictEqual(actualContent, expectedContent)
   })
 
+  it('should extract content from a valid multi block CAR with a range', async () => {
+    const cidPath = 'QmStvUMCtXxEb8wRjNSUqWwqHBEDhmnEd5nHp5siV7bm1Z'
+    const filepath = getFixturePath('multi_block_filtered.car')
+    const carStream = fs.createReadStream(filepath)
+
+    const contentItr = await extractVerifiedContent(cidPath, carStream, { rangeStart: 300, rangeEnd: 349 })
+    const buffer = await concatChunks(contentItr)
+    const actualContent = Buffer.from(buffer).toString('base64')
+
+    // To get this value:
+    // $ mkdir -p outdir && car x -f multi_block.car outdir
+    // $ dd status=none if=outdir/unknown of=/dev/stdout bs=1 skip=300 count=50 | base64
+    const expectedContent = 'Dubn28NGm5/ycJu4PqXEFrgvN0ys0yAwhuYjl2TV23ruEcDazo4LAzZSKF3JeNfCNgg='
+
+    assert.strictEqual(actualContent, expectedContent)
+  })
+
   it('should verify intermediate path segments', async () => {
     const cidPath =
       'bafybeigeqgfwhivuuxgmuvcrrwvs4j3yfzgljssvnuqzokm6uby4fpmwsa/subdir/hello.txt'