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|
Feature: Neg
Checks that an argument is negative `Numeric`.
```ruby
Contract C::Neg => C::Neg
```
Background:
Given a file named "pos_usage.rb" with:
"""ruby
require "contracts"
C = Contracts
class Example
include Contracts::Core
Contract C::Neg => C::Neg
def double_expense(amount)
amount * 2
end
end
"""
Scenario: Accepts negative integers
Given a file named "accepts_negative_integers.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense(-50)
"""
When I run `ruby accepts_negative_integers.rb`
Then output should contain:
"""
-100
"""
Scenario: Accepts negative floats
Given a file named "accepts_negative_floats.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense(-37.99)
"""
When I run `ruby accepts_negative_floats.rb`
Then output should contain:
"""
-75.98
"""
Scenario: Rejects positive integers
Given a file named "rejects_positive_integers.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense(50)
"""
When I run `ruby rejects_positive_integers.rb`
Then output should contain:
"""
: Contract violation for argument 1 of 1: (ParamContractError)
Expected: Neg,
Actual: 50
Value guarded in: Example::double_expense
With Contract: Neg => Neg
"""
And output should contain "pos_usage.rb:8"
Scenario: Rejects positive floats
Given a file named "rejects_positive_floats.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense(42.50)
"""
When I run `ruby rejects_positive_floats.rb`
Then output should contain:
"""
: Contract violation for argument 1 of 1: (ParamContractError)
Expected: Neg,
Actual: 42.5
Value guarded in: Example::double_expense
With Contract: Neg => Neg
"""
And output should contain "pos_usage.rb:8"
Scenario: Rejects zero
Given a file named "rejects_zero.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense(0)
"""
When I run `ruby rejects_zero.rb`
Then output should contain:
"""
: Contract violation for argument 1 of 1: (ParamContractError)
Expected: Neg,
Actual: 0
Value guarded in: Example::double_expense
With Contract: Neg => Neg
"""
And output should contain "pos_usage.rb:8"
Scenario: Rejects other values
Given a file named "rejects_others.rb" with:
"""ruby
require "./pos_usage"
puts Example.new.double_expense("foo")
"""
When I run `ruby rejects_others.rb`
Then output should contain:
"""
: Contract violation for argument 1 of 1: (ParamContractError)
Expected: Neg,
Actual: "foo"
Value guarded in: Example::double_expense
With Contract: Neg => Neg
"""
And output should contain "pos_usage.rb:8"
|
