Fail more gracefully when finding module files if no file is specified

Previously this would just complain about trying to call `nil.split`.

Author: nicklewis

lib/puppet/file_serving/mount/modules.rb

@@ -5,18 +5,17 @@
 class Puppet::FileServing::Mount::Modules < Puppet::FileServing::Mount
   # Return an instance of the appropriate class.
   def find(path, request)
+    raise "No module specified" if path.to_s.empty?
     module_name, relative_path = path.split("/", 2)
     return nil unless mod = request.environment.module(module_name)
 
     mod.file(relative_path)
   end
 
   def search(path, request)
-    module_name, relative_path = path.split("/", 2)
-    return nil unless mod = request.environment.module(module_name)
-
-    return nil unless path = mod.file(relative_path)
-    [path]
+    if result = find(path, request)
+      [result]
+    end
   end
 
   def valid?

spec/unit/file_serving/mount/modules_spec.rb

@@ -12,6 +12,10 @@
   end
 
   describe "when finding files" do
+    it "should fail if no module is specified" do
+      expect { @mount.find("", @request) }.to raise_error(/No module specified/)
+    end
+
     it "should use the provided environment to find the module" do
       @environment.expects(:module)
 
@@ -37,6 +41,10 @@
   end
 
   describe "when searching for files" do
+    it "should fail if no module is specified" do
+      expect { @mount.find("", @request) }.to raise_error(/No module specified/)
+    end
+
     it "should use the node's environment to search the module" do
       @environment.expects(:module)