Appends the load paths to error message

lib/sprockets/resolve.rb

@@ -60,6 +60,7 @@ def resolve!(path, options = {})
         end
 
         message << " with type '#{options[:accept]}'" if options[:accept]
+        message << "\nChecked in these paths: \n  #{ config[:paths].join("\n  ") }"
 
         raise FileNotFound, message
       end

test/test_resolve.rb

@@ -251,6 +251,18 @@ def setup
       @env.each_logical_path("application.js", /gallery\.css/).to_a
   end
 
+  test "adds paths to exceptions" do
+    random_path = SecureRandom.hex
+    @env.append_path(random_path)
+
+    error = assert_raises(Sprockets::FileNotFound) do
+      uri, _ = @env.resolve!("thisfiledoesnotexistandshouldraiseerrors", {})
+      uri
+    end
+
+    assert_match /#{ random_path }/, error.message
+  end
+
   def resolve(path, options = {})
     uri, _ = @env.resolve(path, options.merge(compat: false))
     uri

test/test_server.rb

@@ -283,7 +283,8 @@ def app
   test "re-throw JS exceptions in the browser" do
     get "/assets/missing_require.js"
     assert_equal 200, last_response.status
-    assert_equal "throw Error(\"Sprockets::FileNotFound: couldn't find file 'notfound' with type 'application/javascript'\\n  (in #{fixture_path("server/vendor/javascripts/missing_require.js")}:1)\")", last_response.body
+    assert_match /Sprockets::FileNotFound: couldn't find file 'notfound' with type 'application\/javascript'/, last_response.body
+    assert_match /(in #{fixture_path("server/vendor/javascripts/missing_require.js")}:1)/, last_response.body
   end
 
   test "display CSS exceptions in the browser" do