My irb

irb(main):006> symbols_as_strings.include?("test_method_names_become_symbols")
=> false
irb(main):007> symbols_as_strings = Symbol.all_symbols.map { |x| x.to_s }
=>
["!",
...
irb(main):008> symbols_as_strings.include?("test_method_names_become_symbols")
=> false
irb(main):009>

My code (pass test case)

def test_method_names_become_symbols
  symbols_as_strings = Symbol.all_symbols.map { |x| x.to_s }
  assert_equal true, symbols_as_strings.include?("test_method_names_become_symbols")
end

Why in source code, it is not

assert_equal false, symbols_as_strings.include?("test_method_names_become_symbols")