[Feature Idea] Record & Replay

[albertalef]

Problem: Manually writing mock outputs is tedious and may not accurately reflect real command behavior. Tests need real output format but shouldn't execute commands every time.

Solution: Record actual command outputs to fixture files during development, then replay them in tests for fast, deterministic execution with real data.

# Record mode - executes real commands and saves output
RubyShell.record("fixtures/git_commands.yml") do
  sh do
    git("status")
    git("log", "-5", oneline: true)
  end
end

# Replay mode - returns recorded output without executing
RubyShell.replay("fixtures/git_commands.yml") do
  sh do
    status = git("status")  # returns recorded output
  end
end

# In RSpec
RSpec.describe "Git operations" do
  around do |example|
    RubyShell.replay("fixtures/git_commands.yml") { example.run }
  end

  it "parses git status" do
    expect(sh { git("status") }).to include("On branch main")
  end
end