Install Aqua.jl if necessary during CI (#356)

Author: dkarrasch

test/runtests.jl

@@ -1,5 +1,18 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 using Test, LinearAlgebra, SparseArrays
+
+# Because julia CI doesn't run stdlib tests via `Pkg.test` test deps must be manually installed if missing
+if Base.find_package("Aqua") === nothing
+    @debug "Installing Aqua.jl for SparseArrays.jl tests"
+    iob = IOBuffer()
+    try
+        Pkg.add("Aqua", io=iob) # Needed for custom julia version resolve tests
+    catch
+        println(String(take!(iob)))
+        rethrow()
+    end
+end
+
 for file in readlines(joinpath(@__DIR__, "testgroups"))
     file == "" && continue # skip empty lines
     include(file * ".jl")