[Reproducible-builds] Bug#794150: FTBFS: Could not find 'minitest' (~> 4.0) - did find: [minitest-5.7.0] (Gem::LoadError)

[Chris West (Faux)]

Source: rake
Version: 10.3.2-2
Severity: serious
Tags: sid
Justification: fails to build from source
User: reproducible-builds at lists.alioth.debian.org
Usertags: ftbfs

Dear Maintainer,

The package fails to build:

"test/test_rake_task_argument_parsing.rb"; require "test/test_rake_pseudo_status.rb"' -- 
/usr/lib/ruby/2.2.0/rubygems/dependency.rb:315:in `to_specs': Could not find 'minitest' (~> 4.0) - did find: [minitest-5.7.0] (Gem::LoadError)
Checked in 'GEM_PATH=/tmp/buildd/.gem/ruby/2.2.0:/var/lib/gems/2.2.0:/usr/lib/x86_64-linux-gnu/rubygems-integration/2.2.0:/usr/share/rubygems-integration/2.2.0:/usr/share/rubygems-integration/2.2:/usr/share/rubygems-integration/all', execute `gem env` for more information
	from /usr/lib/ruby/2.2.0/rubygems/dependency.rb:324:in `to_spec'
	from /usr/lib/ruby/2.2.0/rubygems/core_ext/kernel_gem.rb:64:in `gem'
	from -e:1:in `<main>'
rake aborted!
Command failed with status (1): [/usr/bin/ruby2.2 -w -Ilib:bin:test:. -e 'r...]

Full build log:
https://reproducible.debian.net/rb-pkg/unstable/amd64/rake.html

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.19.0-23-generic (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)