module RatatuiRuby::TestHelper::GlobalState

Helpers for testing code that reads global state.

Applications often read ARGV and ENV at startup. Testing these code paths requires stubbing those constants. Doing it manually is brittle —tests that forget to restore the original values leak state.

These helpers swap the constants, yield to the block, and restore the originals automatically.

Example

def test_parses_command_line_flags
  with_argv(["--verbose", "--log=debug.log"]) do
    app = MyApp.new
    assert app.verbose?
    assert_equal "debug.log", app.log_path
  end
end

def test_reads_api_key_from_environment
  with_env("API_KEY", "test-key-1234") do
    client = APIClient.new
    assert_equal "test-key-1234", client.api_key
  end
end

Public Instance Methods

with_argv (argv) { || ... }

Source

# File lib/ratatui_ruby/test_helper/global_state.rb, line 62
def with_argv(argv)
  original_argv = ARGV.dup
  ARGV.replace(argv)
  yield
ensure
  ARGV.replace(original_argv)
end

Temporarily replaces ARGV for the duration of the block.

argv: An array of strings to use as ARGV.

Example

with_argv(["--help"]) do
  # Code here sees ARGV as ["--help"]
end

with_env (key, value) { || ... }

Source

# File lib/ratatui_ruby/test_helper/global_state.rb, line 94
def with_env(key, value)
  original_value = ENV[key]
  if value.nil?
    ENV.delete(key)
  else
    ENV[key] = value
  end
  yield
ensure
  if original_value.nil?
    ENV.delete(key)
  else
    ENV[key] = original_value
  end
end

Temporarily replaces an environment variable for the duration of the block.

If value is nil, the variable is deleted for the block’s duration.

key: The environment variable name (String).
value: The value to set, or nil to delete.

Example

with_env("DEBUG", "1") do
  # Code here sees ENV["DEBUG"] as "1"
end

with_env("DEBUG", nil) do
  # Code here does not see ENV["DEBUG"]
end