How to use RSpec's should_raise with any kind of exception?

expect { some_method }.to raise_error

RSpec 1 Syntax:

lambda { some_method }.should raise_error

See the documentation (for RSpec 1 syntax) and RSpec 2 documentation for more.


RSpec 2

expect { some_method }.to raise_error
expect { some_method }.to raise_error(SomeError)
expect { some_method }.to raise_error("oops")
expect { some_method }.to raise_error(/oops/)
expect { some_method }.to raise_error(SomeError, "oops")
expect { some_method }.to raise_error(SomeError, /oops/)
expect { some_method }.to raise_error(...){|e| expect(e.data).to eq "oops" }

# Rspec also offers to_not:
expect { some_method }.to_not raise_error
...

Note: raise_error and raise_exception are interchangeable.

RSpec 1

lambda { some_method }.should raise_error
lambda { some_method }.should raise_error(SomeError)
lambda { some_method }.should raise_error(SomeError, "oops")
lambda { some_method }.should raise_error(SomeError, /oops/)
lambda { some_method }.should raise_error(...){|e| e.data.should == "oops" }

# Rspec also offers should_not:
lambda { some_method }.should_not raise_error
...

Note: raise_error is an alias for raise_exception.

Documentation: https://www.relishapp.com/rspec

RSpec 2:

  • https://www.relishapp.com/rspec/rspec-expectations/v/2-13/docs/built-in-matchers/raise-error-matcher

RSpec 1:

  • http://apidock.com/rspec/Spec/Matchers/raise_error
  • http://apidock.com/rspec/Spec/Matchers/raise_exception

Instead of lambda, use expect to:

   expect { some_method }.to raise_error

This is applies for more recent versions of rspec, i.e. rspec 2.0 and up.

See the doco for more.