Fix grouping bug with namespc_name-style functions

Previously, function akin to `git_clone` would get part of their input file path appended, yielding `git2_clone` as the group.

Author: tiennou

lib/docurium.rb

@@ -374,9 +374,9 @@ def group_functions!(data)
         k = key
       end
       group, rest = k.split('_', 2)
-      next if group.empty?
-      if !rest
-        group = value[:file].gsub('.h', '').gsub('/', '_')
+      if group.empty?
+        puts "empty group for function #{key}"
+        next
       end
       data[:functions][key][:group] = group
       func[group] ||= []

test/docurium_test.rb

@@ -175,7 +175,8 @@ def test_can_get_the_full_description_from_multi_liners
   end
 
   def test_can_group_functions
-    assert_equal 15, @data[:groups].size
+    groups = %w(blob commit index lasterror object odb oid reference repository revwalk signature strerror tag tree treebuilder work)
+    assert_equal groups, @data[:groups].map {|g| g[0]}
     group, funcs = @data[:groups].first
     assert_equal 'blob', group
     assert_equal 6, funcs.size