presubmit: Check errorf as well (#1845)

Uppercase all these test errors as well. And extend the presubmit to
check for these in the future. Also do a slightly smarter grep to only
get t.<something>. as (because dump regexp) this also grep over non test
files.

plugin/etcd/cname_test.go

@@ -28,7 +28,7 @@ func TestCnameLookup(t *testing.T) {
 		rec := dnstest.NewRecorder(&test.ResponseWriter{})
 		_, err := etc.ServeDNS(ctxt, rec, m)
 		if err != nil {
-			t.Errorf("expected no error, got %v\n", err)
+			t.Errorf("Expected no error, got %v\n", err)
 			return
 		}
 

plugin/etcd/group_test.go

@@ -25,7 +25,7 @@ func TestGroupLookup(t *testing.T) {
 		rec := dnstest.NewRecorder(&test.ResponseWriter{})
 		_, err := etc.ServeDNS(ctxt, rec, m)
 		if err != nil {
-			t.Errorf("expected no error, got %v\n", err)
+			t.Errorf("Expected no error, got %v\n", err)
 			continue
 		}
 

plugin/etcd/multi_test.go

@@ -27,7 +27,7 @@ func TestMultiLookup(t *testing.T) {
 		rec := dnstest.NewRecorder(&test.ResponseWriter{})
 		_, err := etc.ServeDNS(ctxt, rec, m)
 		if err != nil {
-			t.Errorf("expected no error, got %v\n", err)
+			t.Errorf("Expected no error, got %v\n", err)
 			return
 		}
 

plugin/etcd/other_test.go

@@ -29,7 +29,7 @@ func TestOtherLookup(t *testing.T) {
 		rec := dnstest.NewRecorder(&test.ResponseWriter{})
 		_, err := etc.ServeDNS(ctxt, rec, m)
 		if err != nil {
-			t.Errorf("expected no error, got %v\n", err)
+			t.Errorf("Expected no error, got %v\n", err)
 			continue
 		}
 

plugin/etcd/stub_test.go

@@ -58,7 +58,7 @@ func TestStubLookup(t *testing.T) {
 			continue
 		}
 		if err != nil {
-			t.Errorf("expected no error, got %v for %s\n", err, m.Question[0].Name)
+			t.Errorf("Expected no error, got %v for %s\n", err, m.Question[0].Name)
 		}
 		resp := rec.Msg
 		if resp == nil {