exercism/elixir/strain/test/strain_test.exs

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Elixir
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2024-03-10 12:53:48 +00:00
defmodule StrainTest do
use ExUnit.Case
defp is_odd?(n), do: rem(n, 2) == 1
defp is_even?(n), do: rem(n, 2) == 0
describe "keep" do
# @tag :pending
test "on empty list returns empty list" do
assert Strain.keep([], fn _ -> true end) == []
end
# @tag :pending
test "keep everything" do
assert Strain.keep([1, 3, 5], fn _ -> true end) == [1, 3, 5]
end
# @tag :pending
test "keep nothing" do
assert Strain.keep([1, 3, 5], fn _ -> false end) == []
end
# @tag :pending
test "keep first and last" do
assert Strain.keep([1, 2, 3], &is_odd?/1) == [1, 3]
end
# @tag :pending
test "keep neither first nor last" do
assert Strain.keep([1, 2, 3], &is_even?/1) == [2]
end
# @tag :pending
test "keep strings" do
words = ~w(apple zebra banana zombies cherimoya zelot)
assert Strain.keep(words, &String.starts_with?(&1, "z")) == ~w(zebra zombies zelot)
end
# @tag :pending
test "keep lists" do
rows = [
[1, 2, 3],
[5, 5, 5],
[5, 1, 2],
[2, 1, 2],
[1, 5, 2],
[2, 2, 1],
[1, 2, 5]
]
assert Strain.keep(rows, fn row -> 5 in row end) == [
[5, 5, 5],
[5, 1, 2],
[1, 5, 2],
[1, 2, 5]
]
end
end
describe "discard" do
# @tag :pending
test "on empty list returns empty list" do
assert Strain.discard([], fn _ -> true end) == []
end
# @tag :pending
test "discard everything" do
assert Strain.discard([1, 3, 5], fn _ -> true end) == []
end
# @tag :pending
test "discard nothing" do
assert Strain.discard([1, 3, 5], fn _ -> false end) == [1, 3, 5]
end
# @tag :pending
test "discard first and last" do
assert Strain.discard([1, 2, 3], &is_odd?/1) == [2]
end
# @tag :pending
test "discard neither first nor last" do
assert Strain.discard([1, 2, 3], &is_even?/1) == [1, 3]
end
# @tag :pending
test "discard strings" do
words = ~w(apple zebra banana zombies cherimoya zelot)
assert Strain.discard(words, &String.starts_with?(&1, "z")) == ~w(apple banana cherimoya)
end
# @tag :pending
test "discard arrays" do
rows = [
[1, 2, 3],
[5, 5, 5],
[5, 1, 2],
[2, 1, 2],
[1, 5, 2],
[2, 2, 1],
[1, 2, 5]
]
assert Strain.discard(rows, fn row -> 5 in row end) == [[1, 2, 3], [2, 1, 2], [2, 2, 1]]
end
end
end