Expresenter

Expectation result presenter.

Installation

Add this line to your application's Gemfile:

gem "expresenter"

And then execute:

bundle install

Or install it yourself as:

gem install expresenter

Usage

Assuming that an expectation is an assertion that is either true or false, qualifying it with MUST, SHOULD and MAY, we can draw up several scenarios:

Requirement levels	MUST	SHOULD	MAY
Implemented & Matched	`true`	`true`	`true`
Implemented & Not matched	`false`	`true`	`false`
Implemented & Exception	`false`	`false`	`false`
Not implemented	`false`	`false`	`true`

Then,

for a true assertion, a Expresenter::Pass instance can be returned;
for a false assertion, a Expresenter::Fail exception can be raised.

Both class share a same Common interface.

Passed expectations can be classified as:

✅ success
⚠️ warning
💡 info

Failed expectations can be classified as:

❌ failure
💥 error

Instantiation

The following parameters are required to instantiate the result:

actual: Returned value by the challenged subject.
definition: A readable string of the matcher and any expected values.
error: Any possible raised exception.
expected: The expected value.
got: The result of the boolean comparison between the actual value and the expected value through the matcher.
negate: Evaluated to a negative assertion?
level: The requirement level (:MUST, :SHOULD or :MAY).

Examples

A passed expectation:

result = Expresenter.call(true).new(actual: "FOO", definition: 'eq "foo"', error: nil, expected: "foo", got: true, negate: true, level: :MUST)

result.failed? # => false
result.failure? # => false
result.info? # => false
result.warning? # => false
result.to_sym # => :success
result.char # => "."
result.emoji # => "✅"
result.passed? # => true
result.negate? # => true
result.error? # => false
result.success? # => true
result.inspect # => "Expresenter::Pass(actual: \"FOO\", definition: \"eq \\\"foo\\\"\", error: nil, expected: \"foo\", got: true, negate: true, level: :MUST)"
result.definition # => "eq \"foo\""
result.summary # => "expected \"FOO\" not to eq \"foo\""
result.colored_char # => "\e[32m.\e[0m"
result.colored_string # => "\e[32m\e[1mSuccess\e[22m: expected \"FOO\" not to eq \"foo\".\e[0m"
result.message # => "Success: expected \"FOO\" not to eq \"foo\"."
result.to_s # => "Success: expected \"FOO\" not to eq \"foo\"."
result.titre # => "Success"

A failed expectation:

result = Expresenter.call(false).new(actual: "foo", definition: "eq 42", error: Exception.new("BOOM"), expected: 42, got: true, negate: true, level: :MUST)

result.failed? # => true
result.failure? # => false
result.info? # => false
result.warning? # => false
result.to_sym # => :error
result.char # => "E"
result.emoji # => "💥"
result.passed? # => false
result.negate? # => true
result.error? # => true
result.success? # => true
result.inspect # => "Expresenter::Fail(actual: \"foo\", definition: \"eq 42\", error: #<Exception: BOOM>, expected: 42, got: true, negate: true, level: :MUST)"
result.definition # => "eq 42"
result.summary # => "BOOM"
result.colored_char # => "\e[31mE\e[0m"
result.colored_string # => "\e[31m\e[1mException\e[22m: BOOM.\e[0m"
result.message # => "Exception: BOOM."
result.to_s # => "Exception: BOOM."
result.titre # => "Exception"

Return or Raise

To return the results which pass, and to raise the results which fail, the with method is available.

In this example, the result passes, the instance is therefore returned:

Expresenter.call(true).with(actual: "FOO", definition: 'eq "foo"', error: nil, expected: "foo", got: true, negate: true, level: :MUST) # => Expresenter::Pass(actual: "FOO", definition: "eq \"foo\"", error: nil, expected: "foo", got: true, negate: true, level: :MUST)

In this example, the result fails, so the exception is raised:

Expresenter.call(false).with(actual: "foo", definition: "eq 40", error: Exception.new("BOOM"), expected: 42, got: true, negate: true, level: :MUST)

Traceback (most recent call last): 4: from ./bin/console:7:in <main>' 3: from (irb):42 2: from (irb):43:inrescue in irb_binding' 1: from /Users/cyril/github/fixrb/expresenter/lib/expresenter/fail.rb:25:in `with' Expresenter::Fail (Exception: BOOM.)

More Examples

A full list of unit tests can be viewed (and executed) here: ./test.rb

Contact

Home page: https://github.com/fixrb/expresenter
Bugs/issues: https://github.com/fixrb/expresenter/issues

Versioning

Expresenter follows Semantic Versioning 2.0.

License

The gem is available as open source under the terms of the MIT License.

This project is sponsored by: