Calling

A Crystal library for recording method calls. Especially useful for testing if a method is called.

Installation

Add this to your application's shard.yml:

dependencies:
  calling:
    github: mosop/calling

Code Samples

Recording Time.now

module Recorded
  module Time
    extend Calling::Rec

    record_method :now, ::Time do
      ::Time.now
    end
  end
end

Recorded::Time.now # 2017-01-29 12:34:56 +0900
Recorded::Time.now(Time)[0][:result] # 2017-01-29 12:34:56 +0900

Recording sleep

module Recorded
  extend Calling::Rec

  record_method :sleep, :any, {seconds: Float64} do |seconds|
    ::sleep seconds
  end
end

Recorded.sleep 5_f64
Recorded.sleep(Calling::Any)[0][:args][:seconds] # 5.0

Conditional Recording

module Recorded
  {% if flag?(:test) %}
    extend Calling::Rec
  {% else %}
    extend Calling::NoRec
  {% end %}

  record_method :sleep, :any, {seconds: Float64} do
    ::sleep seconds
  end
end

Without the test flag, this code is just expanded like:

module Recorded
  def self.sleep(seconds : Float64)
    ::sleep seconds
  end
end

Defining Recording Methods

A recording method stores information about method calls.

To define recording methods, use the record_method macro.

record_method parameters:

• name (ASTNode) : A method name.
• result (TypeNode | Path) : A result type. It is needed for declaring a type of stored information.
• args (NamedTupleLiteral) : A set of argument names and types. It is needed for declaring a type of stored information.
• &block (Block) : A method body.

Currently, record_method only supports class methods.

The Record Object

Record objects have information about method calls.

To access record objects, call a recording method with its corresponding result type. The result type is given by the second argument of the record_method macro.

Then you get a named tuple that has arrays of record objects by method names.

The record object is a named tuple that has the :args and :result values.

The :args value is a named tuple that has argument values by names.

The :result value is a value that a defined method returns.

Any Result Type

If you don't want to intend a specific result type, set an :any symbol to the second argument of record_method. Then you can access record objects with the Calling::Any type.

If a result type is any, corresponding record objects don't have the :result value.

Usage

require "calling"

and see:

• Code Samples