[DRE-maint] Bug#794267: FTBFS: "in `block in const_missing': uninitialized constant RSpec::Runner (NameError)"

[Chris West (Faux)]

Source: ruby-merb-assets
Version: 1.1.3-2
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:

/usr/bin/ruby2.1 /usr/bin/rspec --pattern ./spec/\*_spec.rb
 ~ No Gemfile found! If you're generating new app with merb-gen this is fine, otherwise run: bundle init to create Gemfile
Digest::Digest is deprecated; use Digest
/usr/lib/ruby/vendor_ruby/rspec/core.rb:179:in `block in const_missing': uninitialized constant RSpec::Runner (NameError)
	from /usr/lib/ruby/vendor_ruby/rspec/core.rb:179:in `fetch'
	from /usr/lib/ruby/vendor_ruby/rspec/core.rb:179:in `const_missing'
	from /tmp/buildd/ruby-merb-assets-1.1.3/spec/spec_helper.rb:21:in `<top (required)>'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /usr/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from /tmp/buildd/ruby-merb-assets-1.1.3/spec/merb-assets_spec.rb:1:in `<top (required)>'
	from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1327:in `load'
	from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1327:in `block in load_spec_files'
	from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1325:in `each'
	from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1325:in `load_spec_files'
	from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:103:in `setup'
	from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:89:in `run'
	from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:74:in `run'
	from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:42:in `invoke'
	from /usr/bin/rspec:4:in `<main>'
/usr/bin/ruby2.1 /usr/bin/rspec --pattern ./spec/\*_spec.rb failed
ERROR: Test "ruby2.1" failed. Exiting.

Full build log:
https://reproducible.debian.net/rb-pkg/unstable/amd64/ruby-merb-assets.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)