add test 4 peak-shift

test/runtests.jl

@@ -29,6 +29,34 @@ begin # empty eeg topoplot
     @test_figure("nullInterpolator", f)
 end
 
+@testset "peaks" begin
+    # 4 coordinates with one peak
+    positions = Point2f[(-1, 0), (0, -1), (1, 0), (0, 1)]
+    i = 1
+    peak_xy = positions[i]
+    data = zeros(length(positions))
+    data[i] = 1
+    fig = topoplot(data, positions)
+    # tighten the limits so that the limits of the axis and the data will match
+    tightlimits!(fig.axis)
+
+    # retrieve the interpolated data
+    m = fig.plot.plots[].color[]
+    # get the limits of the axes and data
+    rect = fig.axis.targetlimits[]
+    minx, miny = minimum(rect)
+    maxx, maxy = maximum(rect)
+    # recreate the coordinates of the data
+    x = range(minx, maxx, length=size(m, 1))
+    y = range(miny, maxy, length=size(m, 2))
+    xys = Point2f.(x, y')
+
+    # find the highest point
+    _, i = findmax(x -> isnan(x) ? -Inf : x, m)
+    xy = xys[i]
+    @test isapprox(xy, peak_xy; atol=0.02)
+end
+
 # begin
 #     f = Figure(resolution=(1000, 1000))
 #     s = Slider(f[:, 1], range=1:size(data, 2), startvalue=351)