Function TestImportDeduplication

protocols/cpc/fetcher/fetcher_test.go:455–490

Tests that blocks arriving from various sources (multiple propagations, hash announces, etc) do not get scheduled for import multiple times.

(t *testing.T)

// Tests that blocks arriving from various sources (multiple propagations, hash
// announces, etc) do not get scheduled for import multiple times.
func TestImportDeduplication(t *testing.T) {
	// Create two blocks to import (one for duplication, the other for stalling)
	hashes, blocks := makeChain(2, 0, genesis)

	// Create the tester and wrap the importer with a counter
	tester := newTester()
	headerFetcher := tester.makeHeaderFetcher("valid", blocks, -gatherSlack)
	bodyFetcher := tester.makeBodyFetcher("valid", blocks, 0)

	counter := uint32(0)
	tester.fetcher.insertChain = func(blocks types.Blocks) (int, error) {
		atomic.AddUint32(&counter, uint32(len(blocks)))
		return tester.insertChain(blocks)
	}
	// Instrument the fetching and imported events
	fetching := make(chan []common.Hash)
	imported := make(chan *types.Block, len(hashes)-1)
	tester.fetcher.fetchingHook = func(hashes []common.Hash) { fetching <- hashes }
	tester.fetcher.importedHook = func(block *types.Block) { imported <- block }

	// Announce the duplicating block, wait for retrieval, and also propagate directly
	tester.fetcher.Notify("valid", hashes[0], 1, time.Now().Add(-arriveTimeout), headerFetcher, bodyFetcher)
	<-fetching

	tester.fetcher.Enqueue("valid", blocks[hashes[0]])
	tester.fetcher.Enqueue("valid", blocks[hashes[0]])
	tester.fetcher.Enqueue("valid", blocks[hashes[0]])

	// Fill the missing block directly as if propagated, and check import uniqueness
	tester.fetcher.Enqueue("valid", blocks[hashes[1]])
	verifyImportCount(t, imported, 2)

	if counter != 2 {
		t.Fatalf("import invocation count mismatch: have %v, want %v", counter, 2)
	}
}

// Tests that blocks with numbers much lower or higher than out current head get
// discarded to prevent wasting resources on useless blocks from faulty peers.