use StableRNGs for testing

Project.toml

@@ -49,6 +49,7 @@ RecipesPipeline = "0.1.7"
 Reexport = "0.2"
 Requires = "1"
 Showoff = "0.3.1"
+StableRNGs = "0.1.1"
 StatsBase = "0.32, 0.33"
 julia = "1"
 
@@ -63,6 +64,7 @@ LibGit2 = "76f85450-5226-5b5a-8eaa-529ad045b433"
 OffsetArrays = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
 PGFPlotsX = "8314cec4-20b6-5062-9cdb-752b83310925"
 RDatasets = "ce6b1742-4840-55fa-b093-852dadbb1d8b"
+StableRNGs = "860ef19b-820b-49d6-a774-d7a799459cd3"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 StatsPlots = "f3b207a7-027a-5e70-b257-86293d7955fd"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
@@ -70,4 +72,4 @@ UnicodePlots = "b8865327-cd53-5732-bb35-84acbb429228"
 VisualRegressionTests = "34922c18-7c2a-561c-bac1-01e79b2c4c92"
 
 [targets]
-test = ["Distributions", "FileIO", "Gtk", "ImageMagick", "Images", "LibGit2", "OffsetArrays", "PGFPlotsX", "HDF5", "RDatasets", "StaticArrays", "StatsPlots", "Test", "UnicodePlots", "VisualRegressionTests"]
+test = ["Distributions", "FileIO", "Gtk", "ImageMagick", "Images", "LibGit2", "OffsetArrays", "PGFPlotsX", "HDF5", "RDatasets", "StableRNGs", "StaticArrays", "StatsPlots", "Test", "UnicodePlots", "VisualRegressionTests"]

test/imgcomp.jl

@@ -1,5 +1,21 @@
 import Plots._current_plots_version
 
+# replace `f(args...)` with `f(rng, args...)` for `f ∈ (rand, randn)`
+function replace_rand!(ex) end
+function replace_rand!(ex::Expr)
+   for arg in ex.args
+       replace_rand!(arg)
+   end
+   if ex.head === :call && ex.args[1] ∈ (:rand, :randn)
+       pushfirst!(ex.args, ex.args[1])
+       ex.args[2] = :rng
+   end
+end
+function fix_rand!(ex)
+    replace_rand!(ex)
+    pushfirst!(ex.args[1].args, :(rng = StableRNG(1234)))
+end
+
 function image_comparison_tests(pkg::Symbol, idx::Int; debug = false, popup = !is_ci(), sigma = [1,1], tol = 1e-2)
     Plots._debugMode.on = debug
     example = Plots._examples[idx]
@@ -8,8 +24,6 @@ function image_comparison_tests(pkg::Symbol, idx::Int; debug = false, popup = !i
     backend(pkg)
     backend()
     default(size=(500,300))
-    # ensure consistent results
-    Random.seed!(1234)
 
     fn = "ref$idx.png"
     reffn = reference_file(pkg, idx, _current_plots_version)
@@ -19,6 +33,7 @@ function image_comparison_tests(pkg::Symbol, idx::Int; debug = false, popup = !i
     func = (fn, idx) -> begin
         expr = Expr(:block)
         append!(expr.args, example.exprs)
+        fix_rand!(expr)
         eval(expr)
         png(fn)
     end

test/runtests.jl

@@ -2,6 +2,7 @@ import ImageMagick
 using VisualRegressionTests
 using Plots
 using Random
+using StableRNGs
 using Test
 using FileIO
 using Gtk