Extended match

This library is meant to provide an ergonomic way to pattern match and bind data in complex types such as maps and structs during testing.

Build status Hex.pm version Hex.pm downloads

installation

Installation

The package can be installed by adding exmatch to your list of dependencies in mix.exs:

defp deps do
  [
    {:exmatch, "~> 0.8.0", only: [:dev, :test]}
  ]
end

usage

Usage

The library depends on ExUnit.AssertionError and therefore is meant to be used only in testing.

Notice

The examples below display the output you would see when testing using ExUnit. Using plain IEx environment will use basic struct formatter different from ExUnit.CLIFormatter.

iex> ExMatch.match(%{a: 1, b: 2, c: 3}, %{c: 3, a: 2, b: {1, 0}})
** (ExUnit.AssertionError)
left:  %{a: 1, b: 2}
right: %{a: 2, b: {1, 0}}

iex> ExMatch.match([10, eleven, _], [Decimal.new("10"), 11, 12], [{Decimal, [:match_integer]}])
iex> eleven == 11
true
iex> ExMatch.match(%Decimal{coef: ^eleven, exp: 1 - 1, sign: 1}, Decimal.add(1, eleven))
** (ExUnit.AssertionError)
left:  %Decimal{coef: ^eleven = 11, exp: 1 - 1 = 0, sign: 1}
right: %Decimal{coef: 12, exp: 0, sign: 1}

iex> alias ExMatchTest.{Dummy, Dummy1}
iex> ExMatch.match(%Dummy{
...>    a: %Dummy1{a: 1},
...>    b: ~U[2022-02-19 05:10:08.387165Z]
...>  }, %Dummy{
...>    a: %Dummy{a: 1},
...>    b: Timex.parse!("2022-02-19 14:55:08.387165+09:45", "{ISO:Extended}")
...>  })
** (ExUnit.AssertionError)
left:  %ExMatchTest.Dummy{a: %(ExMatchTest.Dummy1, [])}
right: %ExMatchTest.Dummy{a: %{__struct__: ExMatchTest.Dummy}}