Implement should_override_forkchoice_update (#11981)

* Implement should_override_forchoice_update

* add tests

* remove unused exported function

* go mod tidy

* fix go mod

* Fix go mod tidy

* Fix context import

* mod tidy

* fix test

* Terence's review

* fix test

---------

Co-authored-by: terence tsao <terence@prysmaticlabs.com>

time/slots/slottime.go

@@ -230,3 +230,12 @@ func SyncCommitteePeriodStartEpoch(e primitives.Epoch) (primitives.Epoch, error)
 	}
 	return primitives.Epoch(startEpoch), nil
 }
+
+// SecondsSinceSlotStart returns the number of seconds transcurred since the
+// given slot start time
+func SecondsSinceSlotStart(s primitives.Slot, genesisTime uint64, timeStamp uint64) (uint64, error) {
+	if timeStamp < genesisTime+uint64(s)*params.BeaconConfig().SecondsPerSlot {
+		return 0, errors.New("could not compute seconds since slot start: invalid timestamp")
+	}
+	return timeStamp - genesisTime - uint64(s)*params.BeaconConfig().SecondsPerSlot, nil
+}

time/slots/slottime_test.go

@@ -460,3 +460,26 @@ func TestSyncCommitteePeriodStartEpoch(t *testing.T) {
 		require.Equal(t, test.wanted, e)
 	}
 }
+
+func TestSecondsSinceSlotStart(t *testing.T) {
+	tests := []struct {
+		slot        primitives.Slot
+		genesisTime uint64
+		timeStamp   uint64
+		wanted      uint64
+		wantedErr   bool
+	}{
+		{},
+		{slot: 1, timeStamp: 1, wantedErr: true},
+		{slot: 1, timeStamp: params.BeaconConfig().SecondsPerSlot + 2, wanted: 2},
+	}
+	for _, test := range tests {
+		w, err := SecondsSinceSlotStart(test.slot, test.genesisTime, test.timeStamp)
+		if err != nil {
+			require.Equal(t, true, test.wantedErr)
+		} else {
+			require.Equal(t, false, test.wantedErr)
+			require.Equal(t, w, test.wanted)
+		}
+	}
+}