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@Aerlinger
Created February 7, 2017 10:29
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require "rspec"
def flatten(arr)
return [arr] unless arr.is_a? Array
arr.reduce([]) { |concat, item| concat + flatten(item) }
end
RSpec.describe "Flattening a nested array" do
it "is valid for simple array" do
expect(flatten([[1]])).to eq([1])
end
it "is valid for empty array" do
expect(flatten([[]])).to eq([])
end
it "is valid for partitioned array" do
expect(flatten([[1], [2], [3], [4], [5]])).to eq([1, 2, 3, 4, 5])
end
it "is valid for array wrapped in array" do
expect(flatten([[1, 2, 3, 4, 5]])).to eq([1, 2, 3, 4, 5])
end
it "is valid for deeply nested empty array" do
expect(flatten([[[], [], [], [nil]]])).to eq([nil])
end
it "is valid for deeply nested inhomogeneous array" do
expect(flatten([[[], [{a: [1, [2]]}], ['a'], [nil]]])).to eq([{a: [1, [2]]}, 'a', nil])
end
it "is valid for a flat array" do
expect(flatten([1, 2, 3, 4])).to eq([1, 2, 3, 4])
end
end
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