Module: RPicSim::RSpec::PersistentExpectations

Included in:
Helpers
Defined in:
lib/rpicsim/rspec/persistent_expectations.rb

Overview

This simple module is included in Helpers so it is available in RSpec tests. It provides a way to set expectations on objects that will be checked after every step of the simulation, so you can make sure that the object stays in the state you are expecting it to.

Example:

b = []
expecting b => satisfy { |lb| lb.size < 10 }
20.times do
  b << 0
  check_expectations  # => raises an error once b has 10 elements
end

For more information, see PersistentExpectations.

Instance Method Summary collapse

Instance Method Details

#check_expectations ⇒ Object

Checks the expectations; if any object does not match its matcher then it raises an error.



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# File 'lib/rpicsim/rspec/persistent_expectations.rb', line 31

def check_expectations
  expectations.each do |subject, matcher|
    expect(subject).to matcher if matcher
  end
  nil
end

#expectations ⇒ Hash

Returns the current set of persistent expectations. The keys are the objects under test and the values are matchers that we expect to match the object.

Returns:

  • (Hash) 


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# File 'lib/rpicsim/rspec/persistent_expectations.rb', line 25

def expectations
  @expectations ||= {}
end

#expecting(hash) ⇒ Object

Adds or removes expectations. The argument should be a hash that associates objects to matchers. A matcher can be any bit of Ruby code that you would be able write in RSpec in place of MATCHER in the code below:

expect(object).to MATCHER

For example, you could do:

expecting main_output_pin: be_driving_high

To remove an expectation on an object, just provide nil for the matcher.

If given a block, applies the new expectations, executes the block, then resets expectations to their former state. Expectation blocks may be nested and freely mixed with other calls to `expecting`.



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# File 'lib/rpicsim/rspec/persistent_expectations.rb', line 55

def expecting(hash)
  if block_given?
    saved_expectations = expectations.clone
    begin
      expecting(hash)
      yield
    ensure
      @expectations = saved_expectations
    end
  else
    expectations.merge! hash
  end
end