fix jupyter (#3090)

* fix jupyter

* Update runtests.jl

* Update runtests.jl

src/ijulia.jl

@@ -4,7 +4,7 @@ const use_local_plotlyjs = Ref(false)
 
 function _init_ijulia_plotting()
     # IJulia is more stable with local file
-    use_local_plotlyjs[] = isfile(plotly_local_file_path[])
+    use_local_plotlyjs[] = plotly_local_file_path[] === nothing ? false : isfile(plotly_local_file_path[])
 
     ENV["MPLBACKEND"] = "Agg"
 end

test/runtests.jl

@@ -11,7 +11,9 @@ import GeometryTypes, GeometryBasics
 using Dates
 using RecipesBase
 
+
 @testset "Plotly standalone" begin
+    @test_nowarn Plots._init_ijulia_plotting()
     @test Plots.plotly_local_file_path[] === nothing
     temp = Plots.use_local_dependencies[]
     withenv("PLOTS_HOST_DEPENDENCY_LOCAL" => true) do
@@ -19,6 +21,7 @@ using RecipesBase
         @test Plots.plotly_local_file_path[] isa String
         @test isfile(Plots.plotly_local_file_path[])
         @test Plots.use_local_dependencies[] = true
+        @test_nowarn Plots._init_ijulia_plotting()
     end
     Plots.plotly_local_file_path[] = nothing
     Plots.use_local_dependencies[] = temp