plotter: UnixTimeTicks is not time.Location agnostic

[kortschak]

I ran tests today and found that the dates shown on the time series test were off by one. I suspect this is due to timezone since I am running this in Australia.

/cc @sbinet

[sbinet]

hum... I thought using time.UTC would take care of that:
https://github.com/gonum/plot/blob/master/plotter/timeseries_test.go#L34

perhaps this would work better?

diff --git a/plotter/timeseries_test.go b/plotter/timeseries_test.go
index 9954874..c4ed9c3 100644
--- a/plotter/timeseries_test.go
+++ b/plotter/timeseries_test.go
@@ -16,6 +16,10 @@ import (
        "github.com/gonum/plot/vg/draw"
 )

+var (
+       location = time.FixedZone("Europe/Paris", 42)
+)
+
 // Example_timeSeries draws a time series.
 func Example_timeSeries() {
        // randomPoints returns some random x, y points
@@ -31,7 +35,7 @@ func Example_timeSeries() {
                )
                pts := make(XYs, n)
                for i := range pts {
-                       date := time.Date(2007+i, month, day, hour, min, sec, nsec, time.UTC).Unix()
+                       date := time.Date(2007+i, month, day, hour, min, sec, nsec, location).Unix()
                        pts[i].X = float64(date)
                        pts[i].Y = float64(pts[i].X+10*rand.Float64()) * 1e-9
                }

[kortschak]

No, this does not fix the problem.

[kortschak]

This is working for me now.