[DRE-maint] Bug#830096: Tests fail when testing installed package

[Christian Hofstaedtler]

Package: ruby-diffy
Version: 3.0.6-1
Severity: important
X-Debbugs-CC: debian-ruby at lists.debian.org

Dear Maintainer,

your package tests fail when testing the installed package:

$ autopkgtest -B -- schroot unstable-amd64-sbuild
[...]
autopkgtest [00:27:55]: test command1: gem2deb-test-runner --autopkgtest 2>&1
autopkgtest [00:27:55]: test command1: [-----------------------

┌──────────────────────────────────────────────────────────────────────────────┐
│ Run tests for ruby2.3 from debian/ruby-tests.rake                            │
└──────────────────────────────────────────────────────────────────────────────┘

mv lib .gem2deb.lib
RUBYLIB=. GEM_PATH= ruby2.3 -S rake -f debian/ruby-tests.rake
/usr/bin/ruby2.3 /usr/bin/rspec --pattern ./spec/\*_spec.rb
/usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- /tmp/autopkgtest.TNgJ6v/build.fB1/real-tree/lib/diffy (LoadError)
        from /usr/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /tmp/autopkgtest.TNgJ6v/build.fB1/real-tree/spec/diffy_spec.rb:2:in `<top (required)>'
        from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1361:in `load'
        from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1361:in `block in load_spec_files'
        from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1359:in `each'
        from /usr/lib/ruby/vendor_ruby/rspec/core/configuration.rb:1359:in `load_spec_files'
        from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:106:in `setup'
        from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:92:in `run'
        from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:78:in `run'
        from /usr/lib/ruby/vendor_ruby/rspec/core/runner.rb:45:in `invoke'
        from /usr/bin/rspec:4:in `<main>'
/usr/bin/ruby2.3 /usr/bin/rspec --pattern ./spec/\*_spec.rb failed
mv .gem2deb.lib lib
autopkgtest [00:27:56]: test command1: -----------------------]
autopkgtest [00:27:56]: test command1:  - - - - - - - - - - results - - - - - - - - - -
command1             FAIL non-zero exit status 1

-- 
 ,''`.  Christian Hofstaedtler <zeha at debian.org>
: :' :  Debian Developer
`. `'   7D1A CFFA D9E0 806C 9C4C  D392 5C13 D6DB 9305 2E03
  `-