Dates/io tests fail on master when networking is unavailable

[sostock]

When networking is unavailable, some Dates/io tests fail due to the module name not being printed, e.g.:

Error in testset Dates/io:
Test Failed at /home/sebastian/Development/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:10
  Expression: sprint(show, Dates.Date(1, 1, 1)) == "Dates.Date(\"0001-01-01\")"
   Evaluated: "Date(\"0001-01-01\")" == "Dates.Date(\"0001-01-01\")"
Error in testset Dates/io:
Test Failed at /home/sebastian/Development/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:19

This does not happen with a internet connection.

[fredrikekre]

This just looks like #23806, #29466. I don't see how network access would change the printing.

[sostock]

I also don’t see how networking would change the printing. However, Base.runtests prints a warning about skipping some tests (even when I only run the Dates tests). Maybe this affects printing?

julia> Base.runtests("Dates")
┌ Warning: Networking unavailable: Skipping tests [Sockets, LibGit2]
└ @ Main ~/Development/julia/usr/share/julia/test/choosetests.jl:151

[ssikdar1]

I can create the same problem be with the networking on by comparing the output of
Base.runtests(["Dates/types", "Dates/io"]) and Base.runtests(["Dates/io"])

Running Base.runtests(["Dates/types", "Dates/io"]) everything passes. Running Base.runtests(["Dates/io"]) gives the same type errors @sostock found. Somehow something seems different about show in certain cases.

julia> VERSION
v"1.5.0-DEV.236"

julia> Base.runtests(["Dates/types", "Dates/io"])
Test    (Worker) | Time (s) | GC (s) | GC % | Alloc (MB) | RSS (MB)
Dates/types  (2) |        started at 2020-02-06T10:29:33.04
Dates/io     (3) |        started at 2020-02-06T10:29:33.124
Dates/types  (2) |     1.91 |   0.08 |  4.1 |     218.10 |   251.75
Dates/io     (3) |     9.56 |   0.22 |  2.3 |    1004.87 |   273.75

Test Summary: | Pass  Total
  Overall     |  537    537
    SUCCESS

julia> Base.runtests(["Dates/io"])
Test  (Worker) | Time (s) | GC (s) | GC % | Alloc (MB) | RSS (MB)
Dates/io   (1) |        started at 2020-02-06T10:29:56.574
string/show representation of Date: Test Failed at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:10
  Expression: sprint(show, Dates.Date(1, 1, 1)) == "Dates.Date(\"0001-01-01\")"
   Evaluated: "Date(\"0001-01-01\")" == "Dates.Date(\"0001-01-01\")"
Stacktrace:
 [1] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:10
 [2] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Test/src/Test.jl:1114
 [3] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:9
string/show representation of Date: Test Failed at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:19
  Expression: sprint(show, Dates.DateTime(2000, 1, 1, 0, 0, 0, 1)) == "Dates.DateTime(\"2000-01-01T00:00:00.001\")"
   Evaluated: "DateTime(\"2000-01-01T00:00:00.001\")" == "Dates.DateTime(\"2000-01-01T00:00:00.001\")"
Stacktrace:
 [1] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:19
 [2] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Test/src/Test.jl:1114
 [3] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:9
string/show representation of Time: Test Failed at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:41
  Expression: sprint(show, t) == shown
   Evaluated: "Time(0)" == "Dates.Time(0)"
Stacktrace:
 [1] macro expansion at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:41 [inlined]
 [2] macro expansion at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Test/src/Test.jl:1114 [inlined]
 [3] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:27
string/show representation of Time: Test Failed at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:42
  Expression: repr(t) == shown
   Evaluated: "Time(0)" == "Dates.Time(0)"
Stacktrace:
 [1] macro expansion at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:42 [inlined]
 [2] macro expansion at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Test/src/Test.jl:1114 [inlined]
 [3] top-level scope at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:27
string/show representation of Time: Test Failed at /Users/ssikdar1/julia/usr/share/julia/stdlib/v1.5/Dates/test/io.jl:41

[ssikdar1]

Seems the issue is here:

julia/test/runtests.jl

Lines 68 to 73 in 4c67921

	n = 1
	if net_on
	n = min(Sys.CPU_THREADS, length(tests))
	n > 1 && addprocs_with_testenv(n)
	LinearAlgebra.BLAS.set_num_threads(1)
	end

Where in the cases where n > 1 Distributed.addproc is being called and the tests pass.
When n = 1 ( the network being turned off => net_on = false and length(tests) = 1 ) addproc isn't called and the tests fail.

I tried a diff like this:

--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -68,10 +68,13 @@ cd(@__DIR__) do
     n = 1
     if net_on
         n = min(Sys.CPU_THREADS, length(tests))
-        n > 1 && addprocs_with_testenv(n)
+        n >= 1 && addprocs_with_testenv(n)
         LinearAlgebra.BLAS.set_num_threads(1)
+    else
+        addprocs_with_testenv(n)
     end

and both networking off and Base.runtests(["Dates/io"]) passed. But I'm not sure if that's the best solution or not.

[ssikdar1]

It seems when cff873b was introduced the using Dates
caused situation similar to this:

julia> using Dates

julia> module Foo
       using Dates
       f() = sprint(show, Dates.Date(1, 1, 1))
       end
Main.Foo

julia> Foo.f()
"Date(1, 1, 1)"

Where there are some tests in Dates/test/io.jl using sprint(show...) , for example

https://github.com/JuliaLang/julia/blob/master/stdlib/Dates/test/io.jl#L19

    @test sprint(show, Dates.DateTime(2000, 1, 1, 0, 0, 0, 1)) == "Dates.DateTime(\"2000-01-01T00:00:00.001\")"

that are expecting this behavior:

julia> module Foo
       using Dates
       f() = sprint(show, Dates.Date(1, 1, 1))
       end
Main.Foo

julia> Foo.f()
"Dates.Date(1, 1, 1)"

It works for most test situations because in runtests.jl, addprocs_with_testenv(n) will be
called, which seems to rest the imports? However in cases where n=1, Dates has already been imported causing any tests with sprint(show...) to fail.

[nico202]

Still happens on v1.6.0

[Zentrik]

runtests(["Dates/io"]) still falls on master.