Add new tests to presubmit, fix errors

perf/go/filetilestore/filestore.go

 package filetilestore
 
 import (
         "encoding/gob"
         "fmt"
         "io/ioutil"
         "os"
         "path"
         "path/filepath"
         "sort"
@@ skipping 41 matching lines @@
 
         // Cache for recently used tiles.
         cache *lru.Cache
 
         // Mutex for ensuring safe access to the cache and lastTile.
         lock sync.Mutex
 }
 
 // tileFilename creates the filename for the given tile scale and index for the
 // given FileTileStore.
-func (store FileTileStore) tileFilename(scale, index int) (string, error) {
+func (store *FileTileStore) tileFilename(scale, index int) (string, error) {
         if scale < 0 || index < 0 {
                 return "", fmt.Errorf("Scale %d and Index %d must both be >= 0", scale, index)
         }
         return path.Join(store.dir, store.datasetName, fmt.Sprintf("%d/%04d.gob", scale, index)), nil
 }
 
 // fileTileTemp creates a unique temporary filename for the given tile scale and
 // index for the given FileTileStore. Used during Put() so that writes update
 // atomically.
-func (store FileTileStore) fileTileTemp(scale, index int) (*os.File, error) {
+func (store *FileTileStore) fileTileTemp(scale, index int) (*os.File, error) {
         if scale < 0 || index < 0 {
                 return nil, fmt.Errorf("Scale %d and Index %d must both be >= 0", scale, index)
         }
         dir := path.Join(store.dir, TEMP_TILE_DIR_NAME)
         if err := os.MkdirAll(dir, 0755); err != nil {
                 return nil, fmt.Errorf("Error creating directory for temp tile %s: %s", dir, err)
         }
         return ioutil.TempFile(dir, fmt.Sprintf("%d-%04d-gob-", scale, index))
 }
 
@@ skipping 245 matching lines @@
 
                 // Refresh the lastTile entries periodically.
                 go func() {
                         for _ = range time.Tick(checkEvery) {
                                 store.refreshLastTiles()
                         }
                 }()
         }
         return store
 }