model-state-objects

An experimental sort-of framework intended to be used for building model-based UI tests.

The basic concept is that UI states are abstractions of where a user might be in the UI, while the App state includes more detailed hidden data. For example, in a web app with different account types, there would be UI states for, say, the log-in page and an account page, while the App state would contain information on the user's account level and whether ze is logged in or not.

In order to simplify app state for analysis, it has a #summarize method which produces an app state summary. This serves two purposes:

1. Multiple real app states can be condensed into a few app state summaries by throwing away information. This helps combat state space explosion.

2. Transitions, which are defined at the UI state level, define what will happen to the summaries. This makes the state machine deterministic, and makes it possible to simulate the state machine.

By looking at the initial App state (which contains the UI state), and taking transitions a-la breadth-first-search or depth-first-search, we can map out all the possible App state summaries, assuming they are finite.

Usage

spec/example_spec.rb is an example

When using this library, one must define the UI states, an AppState, and the AppStateSummary.

UIState

For each UI state your app has, define a class inheriting from ModelStateObjects::UIState. In its initialize method, define transitions with def_transition, and make sure that the class has a method of the same name with a prepended underscore--this method will be the transition's implementation.

class SomeState < ModelStateObjects::UIState
  def initialize(*args)
    super(*args)
    def_transition :some_transition, SomeOtherState
  end
  def _some_transition
    # The ui automation to click on buttons or fill out fields would
    # go here.
  end
end

If the transition would cause a state change other than simply moving from one UI state to another, def_transition can take a block which manipulates an App state summary, representing what changes should take place.

def_transition :submit_comment, DoneSubmitting do |st|
  st.comment_count += 1
end

AppState and AppStateSummary

I'm still thinking this could be changed in the future. At the moment, they are expected to inherit from ModelStateObjects::AppState and ModelStateObjects::AppStateSummary, and may need to reimplement #summarize and #==.