Ruby: Add tests for Gemfile modeling

ruby/ql/test/library-tests/frameworks/gemfile/Gemfile

@@ -0,0 +1,9 @@
+source "https://rubygems.org"
+
+gem "rails", "7.0.0"
+gem "json", "~> 2.6.0"
+gem "jwt"
+
+gem "loofah", ">= 2"
+
+gem "invalid-version", "abc"

ruby/ql/test/library-tests/frameworks/gemfile/Gemfile.expected

@@ -0,0 +1,8 @@
+gemCalls
+| Gemfile:3:1:3:20 | call to gem | rails | 7.0.0 | 7.0.0 |
+| Gemfile:4:1:4:22 | call to gem | json | ~> 2.6.0 | 2.6.0 |
+| Gemfile:7:1:7:20 | call to gem | loofah | >= 2 | 2 |
+versionBefore
+| 2 | 2.6.0 |
+| 2 | 7.0.0 |
+| 2.6.0 | 7.0.0 |

ruby/ql/test/library-tests/frameworks/gemfile/Gemfile.ql

@@ -0,0 +1,17 @@
+import codeql.ruby.frameworks.Gemfile
+
+query predicate gemCalls(
+  Gemfile::Gem gem, string name, Gemfile::VersionConstraint constraint, string version
+) {
+  name = gem.getName() and
+  constraint = gem.getAVersionConstraint() and
+  version = constraint.getVersion()
+}
+
+query predicate versionBefore(string before, string after) {
+  exists(Gemfile::VersionConstraint c1, Gemfile::VersionConstraint c2 |
+    c1.getVersion() = before and c2.getVersion() = after
+  |
+    c1.getVersion().before(after)
+  )
+}

ruby/ql/test/library-tests/frameworks/gemfile/not_gemfile.rb

@@ -0,0 +1 @@
+gem "this-gem-not-in-gemfile", "1.2"