Module: RatatuiRuby::TestHelper::GlobalState

Included in:
RatatuiRuby::TestHelper
Defined in:
lib/ratatui_ruby/test_helper/global_state.rb

Overview

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

– SPDX-SnippetBegin SPDX-FileCopyrightText: 2026 Kerrick Long SPDX-License-Identifier: MIT-0 ++

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

– SPDX-SnippetEnd ++

Instance Method Summary collapse

Instance Method Details

#with_argv(argv) ⇒ Object

Temporarily replaces ARGV for the duration of the block.

argv

An array of strings to use as ARGV.

Example

– SPDX-SnippetBegin SPDX-FileCopyrightText: 2026 Kerrick Long SPDX-License-Identifier: MIT-0 ++

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

– SPDX-SnippetEnd ++



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# 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

#with_env(key, value) ⇒ Object

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

– SPDX-SnippetBegin SPDX-FileCopyrightText: 2026 Kerrick Long SPDX-License-Identifier: MIT-0 ++

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

– SPDX-SnippetEnd ++



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# 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