add test for magnet download piece stage

internal/stage_magnet_dl_piece.go

@@ -0,0 +1,113 @@
+package internal
+
+import (
+ "fmt"
+ "math/rand"
+ "os"
+ "path"
+ "strings"
+
+ "github.com/codecrafters-io/tester-utils/test_case_harness"
+)
+
+func testMagnetDownloadPiece(stageHarness *test_case_harness.TestCaseHarness) error {
+ type MagnetLinkPieceTest struct {
+ MagnetURL string
+ PieceIndex int
+ PieceHash string
+ PieceLength int64
+ }
+
+ var magnetLinkPieceTests = [][]MagnetLinkPieceTest{
+ {
+ {
+ MagnetURL: "magnet:?xt=urn:btih:ad42ce8109f54c99613ce38f9b4d87e70f24a165&dn=magnet1.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 1,
+ PieceHash: "eda417cb5c1cdbf841125c412da0bec9db8301f3",
+ PieceLength: 262144,
+ },
+ {
+ MagnetURL: "magnet:?xt=urn:btih:ad42ce8109f54c99613ce38f9b4d87e70f24a165&dn=magnet1.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 2,
+ PieceHash: "422f45b1052e2d45da3e2a6516e1bb1f1db00733",
+ PieceLength: 112217,
+ },
+ },
+ {
+ {
+ MagnetURL: "magnet:?xt=urn:btih:c5fb9894bdaba464811b088d806bdd611ba490af&dn=magnet3.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 0,
+ PieceHash: "ca80fd83ffb34d6e1bbd26a8ef6d305827f1cd0a",
+ PieceLength: 262144,
+ },
+ {
+ MagnetURL: "magnet:?xt=urn:btih:c5fb9894bdaba464811b088d806bdd611ba490af&dn=magnet3.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 2,
+ PieceHash: "47076d104d214c0052960ef767262649a8af0ea8",
+ PieceLength: 105656,
+ },
+ },
+ {
+ {
+ MagnetURL: "magnet:?xt=urn:btih:3f994a835e090238873498636b98a3e78d1c34ca&dn=magnet2.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 0,
+ PieceHash: "d78a7f55ddd89fef477bc49d938bc7e4d94094f1",
+ PieceLength: 79752,
+ },
+ {
+ MagnetURL: "magnet:?xt=urn:btih:ad42ce8109f54c99613ce38f9b4d87e70f24a165&dn=magnet1.gif&tr=http%3A%2F%2Fbittorrent-test-tracker.codecrafters.io%2Fannounce",
+ PieceIndex: 0,
+ PieceHash: "3b46a96d9bc3716d1b75da91e6d753a793ad1cef",
+ PieceLength: 262144,
+ },
+ },
+ }
+
+ initRandom()
+
+ randomIndex := rand.Intn(len(magnetLinkPieceTests))
+ tests := magnetLinkPieceTests[randomIndex]
+
+ logger := stageHarness.Logger
+ executable := stageHarness.Executable
+
+ tempDir, err := os.MkdirTemp("", "torrents")
+ if err != nil {
+ logger.Errorln("Couldn't create temp directory")
+ return err
+ }
+
+ for _, t := range tests {
+ expectedFilename := fmt.Sprintf("piece-%d", t.PieceIndex)
+ downloadedFilePath := path.Join(tempDir, expectedFilename)
+
+ logger.Infof("Running ./your_bittorrent.sh magnet_download_piece -o %s %q %d", downloadedFilePath, t.MagnetURL, t.PieceIndex)
+ result, err := executable.Run("magnet_download_piece", "-o", downloadedFilePath, t.MagnetURL, fmt.Sprintf("%d", t.PieceIndex))
+ resultStr := string(result.Stdout)
+
+ if strings.Contains(resultStr, "Connection reset by peer") || strings.Contains(resultStr, "EOF") {
+ logger.Infoln("Connection reset by peer or EOF type of errors can be transient issues (try again), but they can also happen when peers receive unexpected messages (sending a REQUEST message with an incorrect offset/length, block size larger than 16 kb etc.)")
+ if t.PieceLength != 262144 {
+ logger.Infof("Last piece of the file can be less than piece length specified in torrent metadata. For instance, the length of this piece is %d", t.PieceLength)
+ }
+ }
+
+ if err != nil {
+ return err
+ }
+
+ if err = assertExitCode(result, 0); err != nil {
+ return err
+ }
+
+ if err = assertFileSize(downloadedFilePath, t.PieceLength); err != nil {
+ return err
+ }
+
+ if err = assertFileSHA1(downloadedFilePath, t.PieceHash); err != nil {
+ return err
+ }
+ }
+
+ return nil
+}