[DRE-maint] Bug#789088: FTBFS: `require': cannot load such file -- minitest/autorun (LoadError)

[Chris West (Faux)]

Package: ruby-beaneater
Version: 0.3.3
Severity: serious
Justification: fails to build from source (but built successfully in the past)

Dear Maintainer,

The package fails to run the tests:
Coveralls] Using SimpleCov's default settings.
SimpleCov failed to recognize the test framework and/or suite used. Please specify manually using SimpleCov.command_name 'Unit Tests'.
[Coveralls] Outside the Travis environment, not sending data.
/usr/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- minitest/autorun (LoadError)
	from /usr/lib/ruby/2.2.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /home/faux/ruby-beaneater-0.3.3/test/test_helper.rb:5:in `<top (required)>'
[..]

The full build log can be seen on the Reproducible Builds builder:
https://reproducible.debian.net/rb-pkg/unstable/amd64/ruby-beaneater.html

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 3.19.0-20-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)