"Plots.jl is not installed" even though it is

[Foolius]

I did
`Pkg.add("Plots"); Pkg.checkout("Plots", "dev")

Pkg.add("GLVisualize")

Pkg.test("GLVisualize`

and I get

WARNING: Plots.jl is not installed, excluding a lot of interesting examples from the tests and a nice summary. Please consider doing: Pkg.add("Plots"); Pkg.checkout("Plots", "dev")

[SimonDanisch]

Solved in newest release.
Although, on 0.6, GLVisualize needs this to be merged first:
JuliaPlots/Plots.jl#970