                   iex> raise "oops"
                   ** (WhatIsThis) "oops"
                 stacktrace:
-                  test/ex_unit/doc_test_test.exs:#{starting_line+18}: ExUnit.DocTestTest.Invalid (module)
+                  test/ex_unit/doc_test_test.exs:#{starting_line + 18}: ExUnit.DocTestTest.Invalid (module)
            """
 
     assert output =~ """

                left:  "This is a slightly shorter text string."
                right: "This is a much shorter text string."
                stacktrace:
                  test/ex_unit/doc_test_test.exs:#{starting_line+6}: ExUnit.DocTestTest.Invalid (module)
           """

    assert output =~ """

                left:  2
                right: 3
                stacktrace:
                  test/ex_unit/doc_test_test.exs:#{starting_line + 3}: ExUnit.DocTestTest.Invalid (module)
           """

    assert output =~ """
