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|
Feature: Args
Used for `*args` (variadic functions). Takes contract and uses it to validate
every element passed in through `*args`.
```ruby
Contract C::Args[C::Num] => C::Bool
def example(*args)
```
This example contract will validate all arguments passed through `*args` to
accept only numbers.
Background:
Given a file named "args_usage.rb" with:
"""ruby
require "contracts"
C = Contracts
class Example
include Contracts::Core
Contract C::Args[C::Num] => C::Bool
def only_nums(*args)
args.inspect
end
end
"""
Scenario: Accepts no arguments
Given a file named "accepts_no_arguments.rb" with:
"""ruby
require "./args_usage"
puts Example.new.only_nums
"""
When I run `ruby accepts_no_arguments.rb`
Then the output should contain:
"""
[]
"""
Scenario: Accepts one valid argument
Given a file named "accepts_one_argument.rb" with:
"""ruby
require "./args_usage"
puts Example.new.only_nums(42)
"""
When I run `ruby accepts_one_argument.rb`
Then the output should contain:
"""
[42]
"""
Scenario: Accepts many valid arguments
Given a file named "accepts_many_arguments.rb" with:
"""ruby
require "./args_usage"
puts Example.new.only_nums(42, 45, 17, 24)
"""
When I run `ruby accepts_many_arguments.rb`
Then the output should contain:
"""
[42, 45, 17, 24]
"""
Scenario: Rejects invalid argument
Given a file named "rejects_invalid_argument.rb" with:
"""ruby
require "./args_usage"
puts Example.new.only_nums(42, "foo", 17, 24)
"""
When I run `ruby rejects_invalid_argument.rb`
Then the output should contain:
"""
: Contract violation for argument 1 of 4: (ParamContractError)
Expected: (Args[Contracts::Builtin::Num]),
Actual: "foo"
Value guarded in: Example::only_nums
With Contract: Args => Bool
"""
|
