Contents

= Expect Method

Expect is another optional assertion nomenclature available
for use in your tests or specifications. Inspired by Jay Fields'
Expectations library, it provides convenient syntax for creating
exception and case equality assertions.

  require 'ae/expect'

== Underlying Comparison

Expect uses #=== for comparison. So providing an argument and a block to
#expect we can test for a somewhat broader range of compassion than #assert.
For example we can test for a subclass.

  expect Numeric do
    3
  end

  Assertion.assert.raised? do
    expect Numeric do
      "3"
    end
  end


== Exception Expectation

If the comparator is an Exception class or a instance of an Exception class,
then #expect will check to see if the block raises that kind of exception.

  expect StandardError do
    some_undefined_method
  end

  expect Assertion do
    expect(nil)
  end

This is an important distinction to note because it means #expect can not be used
if verify instances of Exception classes.

  Assertion.assert.raised? do
    expect Exception do
      Exception.new
    end
  end


== Regex Expectations

That #expect entails #=== also means we can check for Regexp matches.

  expect /x/ do
    "oooxooo"
  end


== Expected Method

We can use #expected to make the receiver the object of expectation.

  x = "dummy"

  /x/.expected do
    "x"
  end


== Function without Block

Without a block, the receiver is compared to the argument.

  x.expect String


== Functor, or Higher Order Function

Like #assert, #expect can be used used as a *fluid* notation.

  10.expect == 10

In which case it works just like #assert.

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
ae-1.2.3	qed/05_expect.rdoc
ae-1.2	test/demos/05_expect.rdoc