Use Licensee hashes to uniquely identify licenses

Since v6.1.0, Licensee exposes the hash of the license
We can use it to uniquely identify unrecognized licenses,
Thus, tests will fail if the content of an unrecognized license changes

Projects for which no license was found are kept in the whitelist

test/test_grammars.rb

@@ -5,14 +5,16 @@ class TestGrammars < Minitest::Test
 
   # List of projects that are allowed without licenses
   PROJECT_WHITELIST = [
-    "vendor/grammars/factor",
-    "vendor/grammars/go-tmbundle",
-    "vendor/grammars/jflex.tmbundle",
     "vendor/grammars/language-csharp",
-    "vendor/grammars/language-viml",
     "vendor/grammars/sublimeassembly"
   ].freeze
 
+  HASH_WHITELIST = [
+    "ebae2d87e06d3acef075d049fcfc8958c0364863", # go-tmbundle
+    "ff21db2554d69d78b2220db5615b16bbba0788d3", # factor
+    "b9a7428fd036eed8503995e06e989180c276b17d"  # jflex.tmbundle
+  ].freeze
+
   # List of allowed SPDX license names
   LICENSE_WHITELIST = %w[
     apache-2.0
@@ -90,7 +92,10 @@ class TestGrammars < Minitest::Test
   end
 
   def test_submodules_have_approved_licenses
-    unapproved = submodule_licenses.reject { |k,v| LICENSE_WHITELIST.include?(v) || PROJECT_WHITELIST.include?(k) }.map { |k,v| "#{k}: #{v}"}
+    unapproved = submodule_licenses.reject { |k,v| LICENSE_WHITELIST.include?(v) ||
+                                                   PROJECT_WHITELIST.include?(k) ||
+                                                   HASH_WHITELIST.include?(v) }
+                                   .map { |k,v| "#{k}: #{v}"}
     message = "The following submodules have unapproved licenses:\n* #{unapproved.join("\n* ")}\n"
     message << "The license must be added to the LICENSE_WHITELIST in /test/test_grammars.rb once approved."
     assert_equal [], unapproved, message
@@ -139,6 +144,7 @@ class TestGrammars < Minitest::Test
   end
 
   # Given the path to a submodule, return its SPDX-compliant license key
+  # If the license is unrecognized, return its hash
   def submodule_license(submodule)
     # Prefer Licensee to detect a submodule's license
     project = Licensee::FSProject.new(submodule, detect_readme: true)
@@ -155,7 +161,16 @@ class TestGrammars < Minitest::Test
     # Neither Licensee nor our own regex was able to detect the license, let's check the readme
     files = Dir[File.join(ROOT, submodule, "*")]
     if readme = files.find { |file| File.basename(file) =~ /\Areadme\b/i }
-      classify_license(readme)
+      license = classify_license(readme)
+      return license if license
+    end
+
+    # We know a license exists, but no method was able to recognize it.
+    # We return the license hash in this case, to uniquely identify it.
+    if project.license_file
+      return project.license_file.hash
+    elsif project.readme
+      return project.readme.hash
     end
   end