Rspec: "array.should == another_array" but without concern for order

I often want to compare arrays and make sure that they contain the same elements, in any order. Is there a concise way to do this in RSpec?

Here are methods that aren't acceptable:

#to_set

For example:

expect(array.to_set).to eq another_array.to_set

or

array.to_set.should == another_array.to_set

This fails when the arrays contain duplicate items.

#sort

For example:

expect(array.sort).to eq another_array.sort

or

array.sort.should == another_array.sort

This fails when the arrays elements don't implement #<=>

Try array.should =~ another_array

The best documentation on this I can find is the code itself, which is here.

Since RSpec 2.11 you can also use match_array.

array.should match_array(another_array)

Which could be more readable in some cases.

[1, 2, 3].should =~ [2, 3, 1]
# vs
[1, 2, 3].should match_array([2, 3, 1])

I've found =~ to be unpredictable and it has failed for no apparent reason. Past 2.14, you should probably use

expect([1, 2, 3]).to match_array([2, 3, 1])

Use match_array, which takes another array as an argument, or contain_exactly, which takes each element as a separate argument, and is sometimes useful for readability. (docs)

Examples:

expect([1, 2, 3]).to match_array [3, 2, 1]

or

expect([1, 2, 3]).to contain_exactly 3, 2, 1