make seen a non-primitive type

api/internal/crawl/crawler/crawler_test.go

@@ -75,7 +75,7 @@ func newCrawler(matchPrefix string, err error,
 
 // Crawl implements the Crawler interface for testing.
 func (c testCrawler) Crawl(_ context.Context,
-	output chan<- CrawledDocument, _ map[string]struct{}) error {
+	output chan<- CrawledDocument, _ SeenMap) error {
 
 	for i, d := range c.docs {
 		isResource := true
@@ -181,7 +181,7 @@ func TestCrawlGithubRunner(t *testing.T) {
 			defer close(output)
 			defer wg.Done()
 
-			seen := map[string]struct{}{}
+			seen := NewSeenMap()
 			errs := CrawlGithubRunner(context.Background(),
 				output, test.tc, seen)
 
@@ -323,7 +323,7 @@ resources:
 				visited[d.ID()]++
 				return nil
 			},
-			make(map[string]struct{}),
+			NewSeenMap(),
 		)
 		if lv, lc := len(visited), len(tc.corpus); lv != lc {
 			t.Errorf("error: %d of %d documents visited.", lv, lc)