only depend on specific components of linkeddata being used

To avoid dependency conflicts with sub-dependencies of linkeddata not being used. linkeddata is a meta gem that just aggregates a bunch of linked data-related gems.

We still aren't sure why these linkeddata gems have historically been listed as development-only dependencies instead of runtime dependencies. See #375

qa.gemspec

@@ -30,7 +30,20 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rails', '!=5.2.0', '!=5.2.1', '!=5.2.2'
   s.add_development_dependency 'byebug'
   s.add_development_dependency 'engine_cart', '~> 2.0'
-  s.add_development_dependency 'linkeddata'
+
+  # Not sure why these RDF-related gems are only being listed as development dependencies
+  # not general runtime dependencies...
+  # ... maybe meant to be optional dependencies only if you are using related
+  # func? See also the "meta" gem `linkeddata` which includes all of these deps.
+  #
+  # If apps find they need these optional dependencies for linked-data-related
+  # functionality from qa gem, they may find it easiest to include the `linkeddata`
+  # aggregator gem as one of their dependencies.
+  s.add_development_dependency 'rdf-n3', '~> 3.0'
+  s.add_development_dependency 'rdf-rdfxml', '~> 3.0'
+  s.add_development_dependency 'json-ld', '~> 3.0'
+  s.add_development_dependency 'rdf-vocab', '~> 3.0'
+
   s.add_development_dependency 'pry'
   s.add_development_dependency 'pry-byebug'
   s.add_development_dependency 'rspec-rails'

spec/spec_helper.rb

@@ -1,4 +1,10 @@
-require 'linkeddata'
+# Not sure why these RDF-related gems are only being used in CI and not general
+# dependencies... maybe meant to be optional dependencies?
+require 'rdf/n3'
+require 'rdf/rdfxml'
+require 'json/ld'
+require 'rdf/vocab'
+
 require 'json'
 require 'engine_cart'
 require 'byebug' unless ENV['TRAVIS']

spec/test_app_templates/Gemfile.extra

@@ -11,15 +11,6 @@ group :development do
   #
   if ENV['RAILS_VERSION'] && Gem::Version.new(ENV['RAILS_VERSION']) < Gem::Version.new("6.1")
     gem 'psych', '< 4'
-
-    # Some versions of linkeddata dependency depend on yaml-ld gem... yaml-ld 0.0.1
-    # has a dependency on psych 4.x specifically, conflicting with above, bundler
-    # seems to be having trouble resolving to yaml-ld 0.0.2 on it's own.
-    # We don't actually depend on yaml-ld at all ourselves, just trying
-    # to help bundler resolve a tree that works.
-    #
-    # https://github.com/ruby-rdf/linkeddata/issues/16#issuecomment-1239912981
-    gem 'yaml-ld', ">= 0.0.2"
   end
 
   if ENV['RAILS_VERSION'] =~ /^6\.1\./ && ENV['RUBY_VERSION'] =~ /^3\.1\./