Collect facts iteratively

Rather than getting the facts for every filter spec and then discarding
that, this stores the found facts in an array and uses that.

This eliminates a call to FacterDB::get_facts with a very complex
filter.

A quick test in puppet-nginx reduces loading of tests by about 2 seconds
(from ~9 to ~7).

lib/rspec-puppet-facts.rb

@@ -114,14 +114,18 @@ def on_supported_os_implementation(opts = {})
     end
 
     facterversion_obj = Gem::Version.new(facterversion)
+    received_facts = []
 
     # FacterDB may have newer versions of facter data for which it contains a subset of all possible
     # facter data (see FacterDB 0.5.2 for Facter releases 3.8 and 3.9). In this situation we need to
     # cycle through and downgrade Facter versions per platform type until we find matching Facter data.
     filter.each do |filter_spec|
-      version = FacterDB.get_facts(filter_spec).map { |facts| Gem::Version.new(facts[:facterversion]) }.sort.reverse.detect { |v| v <= facterversion_obj }
-      next unless version
-      version = version.to_s
+      facts = FacterDB.get_facts(filter_spec)
+        .select { |facts| Gem::Version.new(facts[:facterversion]) <= facterversion_obj }
+        .max_by { |facts| Gem::Version.new(facts[:facterversion]) }
+
+      next unless facts
+      version = facts[:facterversion]
 
       unless version == facterversion
         if RspecPuppetFacts.spec_facts_strict?
@@ -131,10 +135,9 @@ def on_supported_os_implementation(opts = {})
         RspecPuppetFacts.warning "No facts were found in the FacterDB for Facter v#{facterversion} on #{filter_spec}, using v#{version} instead"
       end
 
-      filter_spec[:facterversion] = "/\\A#{Regexp.escape(version)}/"
+      received_facts << facts
     end
 
-    received_facts = FacterDB::get_facts(filter)
     unless received_facts.any?
       RspecPuppetFacts.warning "No facts were found in the FacterDB for: #{filter.inspect}"
       return {}