Add new tests to presubmit, fix errors

go/gitinfo/gitinfo_test.go

 package gitinfo
 
 import (
         "path/filepath"
         "testing"
         "time"
 
         "skia.googlesource.com/buildbot.git/go/util"
 )
 
@@ skipping 63 matching lines @@
                         length: 1,
                 },
                 {
                         ts:     1406721641,
                         length: 2,
                 },
         }
         for _, tc := range testCases {
                 hashes := r.From(time.Unix(tc.ts, 0))
                 if got, want := len(hashes), tc.length; got != want {
-                        t.Errorf("For ts: %d Length returned is wrong: Got %s Want %d", tc.ts, got, want)
+                        t.Errorf("For ts: %d Length returned is wrong: Got %d Want %d", tc.ts, got, want)
                 }
         }
 }
 
 func TestLog(t *testing.T) {
         tr := util.NewTempRepo()
         defer tr.Cleanup()
 
         r, err := NewGitInfo(filepath.Join(tr.Dir, "testrepo"), false, false)
         if err != nil {
@@ skipping 137 matching lines @@
 
         r, err := NewGitInfo(filepath.Join(tr.Dir, "testrepo"), false, false)
         if err != nil {
                 t.Fatal(err)
         }
 
         if got, want := r.NumCommits(), 2; got != want {
                 t.Errorf("NumCommit wrong number: Got %v Want %v", got, want)
         }
 }