I’ve built the following code (reverse not implemented) to solve the secret_handshake
problem at exercism.io.
But the first test fails…
test Create a handshake for a number wink for 1 (SecretHandshakeTest)
secret_handshake_test.exs:13
Assertion with == failed
code: assert SecretHandshake.commands(1) == ["wink"]
left: ["wink", nil]
right: ["wink"]
stacktrace:
secret_handshake_test.exs:14: (test)
There’s a ["wink", nil]
instead of a ["wink"]
for the 1
case, and I can’t figure out why this is happening.
defmodule SecretHandshake do
@doc """
Determine the actions of a secret handshake based on the binary
representation of the given `code`.
If the following bits are set, include the corresponding action in your list
of commands, in order from lowest to highest.
1 = wink
10 = double blink
100 = close your eyes
1000 = jump
10000 = Reverse the order of the operations in the secret handshake
"""
@spec commands(code :: integer) :: list(String.t())
def commands(code) do
in_binary = decimalToBinary code
to_reverse = true and rem(code, 10000)
commands = []
commands = if div(in_binary, 1000) == 1, do: [getAction(1000)] ++ commands
commands = if div(in_binary, 100) == 1, do: [getAction(100)] ++ commands
commands = if div(in_binary, 10) == 1, do: [getAction(10)] ++ commands
commands = if rem(in_binary, 2) == 1, do: [getAction(1)] ++ commands
end
defp getAction(dec) do
case dec do
1 -> "wink"
10 -> "double blink"
100 -> "close your eyes"
1000 -> "jump"
end
end
defp decimalToBinary(dec) do
dec
|> Integer.to_string(2)
|> String.to_integer
end
end