[DRE-maint] Bug#794259: FTBFS: "JWT secure comparison returns true if strings are equal" fails

[Chris West (Faux)]

Source: ruby-jwt
Version: 1.0.0-2
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
...................FFF..

Failures:

  1) JWT secure comparison returns true if strings are equal
     Failure/Error: expect(JWT.secure_compare("Foo", "Foo")).to be_true
       expected true to respond to `true?` or perhaps you meant `be true` or `be_truthy`
     # ./spec/jwt_spec.rb:127:in `block (3 levels) in <top (required)>'

  2) JWT secure comparison returns false if either input is nil or empty
     Failure/Error: expect(JWT.secure_compare(bad, "Foo")).to be_false
       expected false to respond to `false?` or perhaps you meant `be false` or `be_falsey`
     # ./spec/jwt_spec.rb:132:in `block (4 levels) in <top (required)>'
     # ./spec/jwt_spec.rb:131:in `each'
     # ./spec/jwt_spec.rb:131:in `block (3 levels) in <top (required)>'

  3) JWT secure comparison retuns false if the strings are different
     Failure/Error: expect(JWT.secure_compare("Foo", "Bar")).to be_false
       expected false to respond to `false?` or perhaps you meant `be false` or `be_falsey`
     # ./spec/jwt_spec.rb:138:in `block (3 levels) in <top (required)>'

Finished in 0.34342 seconds (files took 1.12 seconds to load)
23 examples, 3 failures

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