Add test

client/client_test.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 
 	"github.com/transparency-dev/formats/log"
@@ -78,21 +79,51 @@ func mustLoadTestCheckpoints() ([][]byte, []log.Checkpoint) {
 	return raws, cps
 }
 
+// testLogFetcher is a fetcher which reads from the checked-in golden test log
+// data stored in ../testdata/log
 func testLogFetcher(_ context.Context, p string) ([]byte, error) {
 	path := filepath.Join("../testdata/log", p)
 	return os.ReadFile(path)
 }
 
+// fetchCheckpointShim allows fetcher requests for checkpoints to be intercepted.
+type fetchCheckpointShim struct {
+	// Checkpoints holds raw checkpoints to be returned when the fetcher is asked to retrieve a checkpoint path.
+	// The zero-th entry will be returned until Advance is called.
+	Checkpoints [][]byte
+}
+
+// Fetcher intercepts requests for the checkpoint file, returning the zero-th
+// entry in the Checkpoints field. All other requests are passed through
+// to the delegate fetcher.
+func (f *fetchCheckpointShim) Fetcher(deleg Fetcher) Fetcher {
+	return func(ctx context.Context, path string) ([]byte, error) {
+		if strings.HasSuffix(path, "checkpoint") {
+			if len(f.Checkpoints) == 0 {
+				return nil, os.ErrNotExist
+			}
+			r := f.Checkpoints[0]
+			return r, nil
+		}
+		return deleg(ctx, path)
+	}
+}
+
+// Advance causes subsequent intercepted checkpoint requests to return
+// the next entry in the Checkpoints slice.
+func (f *fetchCheckpointShim) Advance() {
+	f.Checkpoints = f.Checkpoints[1:]
+}
+
 func TestCheckLogStateTracker(t *testing.T) {
 	ctx := context.Background()
 	h := rfc6962.DefaultHasher
 
-	lst := NewLogStateTracker(ctx, testLogFetcher, h, testRawCheckpoints[0])
-
 	for _, test := range []struct {
-		desc    string
-		cpRaws  [][]byte
-	}{} {
+		desc       string
+		cpRaws     [][]byte
+		wantCpRaws [][]byte
+	}{
 		{
 			desc: "Consistent",
 			cpRaws: [][]byte{
@@ -103,6 +134,14 @@ func TestCheckLogStateTracker(t *testing.T) {
 				testRawCheckpoints[6],
 				testRawCheckpoints[10],
 			},
+			wantCpRaws: [][]byte{
+				testRawCheckpoints[0],
+				testRawCheckpoints[2],
+				testRawCheckpoints[3],
+				testRawCheckpoints[5],
+				testRawCheckpoints[6],
+				testRawCheckpoints[10],
+			},
 		}, {
 			desc: "Identical CP",
 			cpRaws: [][]byte{
@@ -111,6 +150,12 @@ func TestCheckLogStateTracker(t *testing.T) {
 				testRawCheckpoints[0],
 				testRawCheckpoints[0],
 			},
+			wantCpRaws: [][]byte{
+				testRawCheckpoints[0],
+				testRawCheckpoints[0],
+				testRawCheckpoints[0],
+				testRawCheckpoints[0],
+			},
 		}, {
 			desc: "Identical CP pairs",
 			cpRaws: [][]byte{
@@ -119,6 +164,12 @@ func TestCheckLogStateTracker(t *testing.T) {
 				testRawCheckpoints[5],
 				testRawCheckpoints[5],
 			},
+			wantCpRaws: [][]byte{
+				testRawCheckpoints[0],
+				testRawCheckpoints[0],
+				testRawCheckpoints[5],
+				testRawCheckpoints[5],
+			},
 		}, {
 			desc: "Out of order",
 			cpRaws: [][]byte{
@@ -127,13 +178,32 @@ func TestCheckLogStateTracker(t *testing.T) {
 				testRawCheckpoints[0],
 				testRawCheckpoints[3],
 			},
+			wantCpRaws: [][]byte{
+				testRawCheckpoints[5],
+				testRawCheckpoints[5],
+				testRawCheckpoints[5],
+				testRawCheckpoints[5],
+			},
 		},
 	} {
-		t.Run(test.desc, func(t *testing.T){
-			for i, cpRaw := range test.cpRaws {
-				if err := lst.Update(ctx, cpRaw); err != nil {
+		t.Run(test.desc, func(t *testing.T) {
+			shim := fetchCheckpointShim{Checkpoints: test.cpRaws}
+			f := shim.Fetcher(testLogFetcher)
+			lst, err := NewLogStateTracker(ctx, f, h, testRawCheckpoints[0], testLogVerifier, testOrigin, UnilateralConsensus(f))
+			if err != nil {
+				t.Fatalf("NewLogStateTracker: %v", err)
+			}
+
+			for i := range test.cpRaws {
+				_, _, newCP, err := lst.Update(ctx)
+				if err != nil {
 					t.Errorf("Update %d: %v", i, err)
 				}
+				if got, want := newCP, test.wantCpRaws[i]; !bytes.Equal(got, want) {
+					t.Errorf("Update moved to:\n%s\nwant:\n%s", string(got), string(want))
+				}
+
+				shim.Advance()
 			}
 		})
 	}