Add test to make sure cancel works

syncer/syncer_test.go

@@ -16,8 +16,10 @@ package syncer
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"testing"
+	"time"
 
 	mocks "github.com/coinbase/rosetta-sdk-go/mocks/syncer"
 	"github.com/coinbase/rosetta-sdk-go/types"
@@ -407,6 +409,65 @@ func TestSync_NoReorg(t *testing.T) {
 	mockHandler.AssertExpectations(t)
 }
 
+func TestSync_Cancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	mockHelper := &mocks.Helper{}
+	mockHandler := &mocks.Handler{}
+	syncer := New(networkIdentifier, mockHelper, mockHandler, cancel, WithConcurrency(16))
+
+	// Force syncer to only get part of the way through the full range
+	mockHelper.On("NetworkStatus", ctx, networkIdentifier).Return(&types.NetworkStatusResponse{
+		CurrentBlockIdentifier: &types.BlockIdentifier{
+			Hash:  "block 200",
+			Index: 200,
+		},
+		GenesisBlockIdentifier: &types.BlockIdentifier{
+			Hash:  "block 0",
+			Index: 0,
+		},
+	}, nil).Twice()
+
+	mockHelper.On("NetworkStatus", ctx, networkIdentifier).Return(&types.NetworkStatusResponse{
+		CurrentBlockIdentifier: &types.BlockIdentifier{
+			Hash:  "block 1300",
+			Index: 1300,
+		},
+		GenesisBlockIdentifier: &types.BlockIdentifier{
+			Hash:  "block 0",
+			Index: 0,
+		},
+	}, nil).Twice()
+
+	blocks := createBlocks(0, 1200, "")
+	for _, b := range blocks {
+		mockHelper.On(
+			"Block",
+			mock.AnythingOfType("*context.cancelCtx"),
+			networkIdentifier,
+			&types.PartialBlockIdentifier{Index: &b.BlockIdentifier.Index},
+		).Return(
+			b,
+			nil,
+		).Once()
+		mockHandler.On(
+			"BlockAdded",
+			mock.AnythingOfType("*context.cancelCtx"),
+			b,
+		).Return(
+			nil,
+		).Once()
+	}
+
+	go func() {
+		time.Sleep(1 * time.Second)
+		cancel()
+	}()
+
+	err := syncer.Sync(ctx, -1, 1200)
+	assert.True(t, errors.Is(err, context.Canceled))
+}
+
 func TestSync_Reorg(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())