Spec for an AngularJS filter that injects another filter.

currency.coffee

# NOTE: We're overriding a built-in filter by the same name.

app.filter "currency", (numberFilter) ->
  (text, currencyName) ->
    numberFilter(text) + " " + currencyName

currency_spec.coffee

#= require helpers/angular_helper
#= require filters/currency

describe "currency", ->
  it "appends the provided currency to the formatted number", ->
    module ($provide) ->
      $provide.value "numberFilter", (number) -> "[formatted #{number}]"
      null

    inject (currencyFilter) ->
      expect(currencyFilter(1234, "SEK")).toEqual("[formatted 1234] SEK")