add ElasticManager test

src/elastic.jl

@@ -137,10 +137,13 @@ end
 
 function get_private_ip()
     if Sys.islinux()
-        IPv4(strip(read(`hostname --ip-address`, String)))
+        cmd = `hostname --ip-address`
+    elseif Sys.isapple()
+        cmd = `ipconfig getifaddr en0`
     else
-        error("addr=:auto is only supported on Linux")
+        error("addr=:auto is only supported on Linux and Mac")
     end
+    IPv4(@show strip(read(cmd, String)))
 end
 
 function get_connect_cmd(em::ElasticManager; absolute_exename=true, same_project=true)

test/runtests.jl

@@ -1,2 +1,18 @@
-# only package loading for now
+using Test
 using ClusterManagers
+
+TIMEOUT = 10.
+
+@testset "ElasticManager" begin
+
+    em = ElasticManager(addr=:auto, port=0)
+
+    # launch worker
+    run(`sh -c $(ClusterManagers.get_connect_cmd(em))`, wait=false)
+
+    # wait at most TIMEOUT seconds for it to connect
+    @test :ok == timedwait(TIMEOUT) do
+        length(em.active) == 1
+    end
+
+end