From dc5e05a03a7d3d467160ba9cc93486b24f24ecc1 Mon Sep 17 00:00:00 2001
From: Julio Biason <julio.biason@pm.me>
Date: Thu, 16 Jul 2020 20:35:10 -0300
Subject: [PATCH] DNA -> RNA transformation

---
 elixir/rna-transcription/README.md            | 61 +++++++++++++++++++
 .../lib/rna_transcription.ex                  | 24 ++++++++
 elixir/rna-transcription/mix.exs              | 28 +++++++++
 .../test/rna_transcription_test.exs           | 28 +++++++++
 elixir/rna-transcription/test/test_helper.exs |  2 +
 5 files changed, 143 insertions(+)
 create mode 100644 elixir/rna-transcription/README.md
 create mode 100644 elixir/rna-transcription/lib/rna_transcription.ex
 create mode 100644 elixir/rna-transcription/mix.exs
 create mode 100644 elixir/rna-transcription/test/rna_transcription_test.exs
 create mode 100644 elixir/rna-transcription/test/test_helper.exs

diff --git a/elixir/rna-transcription/README.md b/elixir/rna-transcription/README.md
new file mode 100644
index 0000000..05c0c4a
--- /dev/null
+++ b/elixir/rna-transcription/README.md
@@ -0,0 +1,61 @@
+# RNA Transcription
+
+Given a DNA strand, return its RNA complement (per RNA transcription).
+
+Both DNA and RNA strands are a sequence of nucleotides.
+
+The four nucleotides found in DNA are adenine (**A**), cytosine (**C**),
+guanine (**G**) and thymine (**T**).
+
+The four nucleotides found in RNA are adenine (**A**), cytosine (**C**),
+guanine (**G**) and uracil (**U**).
+
+Given a DNA strand, its transcribed RNA strand is formed by replacing
+each nucleotide with its complement:
+
+* `G` -> `C`
+* `C` -> `G`
+* `T` -> `A`
+* `A` -> `U`
+
+## Running tests
+
+Execute the tests with:
+
+```bash
+$ mix test
+```
+
+### Pending tests
+
+In the test suites, all but the first test have been skipped.
+
+Once you get a test passing, you can unskip the next one by
+commenting out the relevant `@tag :pending` with a `#` symbol.
+
+For example:
+
+```elixir
+# @tag :pending
+test "shouting" do
+  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
+end
+```
+
+Or, you can enable all the tests by commenting out the
+`ExUnit.configure` line in the test suite.
+
+```elixir
+# ExUnit.configure exclude: :pending, trace: true
+```
+
+If you're stuck on something, it may help to look at some of
+the [available resources](https://exercism.io/tracks/elixir/resources)
+out there where answers might be found.
+
+## Source
+
+Hyperphysics [http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html](http://hyperphysics.phy-astr.gsu.edu/hbase/Organic/transcription.html)
+
+## Submitting Incomplete Solutions
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
diff --git a/elixir/rna-transcription/lib/rna_transcription.ex b/elixir/rna-transcription/lib/rna_transcription.ex
new file mode 100644
index 0000000..531cd83
--- /dev/null
+++ b/elixir/rna-transcription/lib/rna_transcription.ex
@@ -0,0 +1,24 @@
+defmodule RnaTranscription do
+  @doc """
+  Transcribes a character list representing DNA nucleotides to RNA
+
+  ## Examples
+
+  iex> RnaTranscription.to_rna('ACTG')
+  'UGAC'
+  """
+  @spec to_rna([char]) :: [char]
+  def to_rna(dna) do
+    Enum.map(dna, &(dna_to_rna(&1)))
+  end
+
+  @spec dna_to_rna(char) :: char
+  def dna_to_rna(strand) do
+    case strand do
+      ?A -> ?U
+      ?C -> ?G
+      ?T -> ?A
+      ?G -> ?C
+    end
+  end
+end
diff --git a/elixir/rna-transcription/mix.exs b/elixir/rna-transcription/mix.exs
new file mode 100644
index 0000000..8a2487c
--- /dev/null
+++ b/elixir/rna-transcription/mix.exs
@@ -0,0 +1,28 @@
+defmodule RnaTranscription.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :rna_transcription,
+      version: "0.1.0",
+      # elixir: "~> 1.8",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    [
+      extra_applications: [:logger]
+    ]
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end
diff --git a/elixir/rna-transcription/test/rna_transcription_test.exs b/elixir/rna-transcription/test/rna_transcription_test.exs
new file mode 100644
index 0000000..b39a23c
--- /dev/null
+++ b/elixir/rna-transcription/test/rna_transcription_test.exs
@@ -0,0 +1,28 @@
+defmodule RnaTranscriptionTest do
+  use ExUnit.Case
+
+  # @tag :pending
+  test "transcribes guanine to cytosine" do
+    assert RnaTranscription.to_rna('G') == 'C'
+  end
+
+  # @tag :pending
+  test "transcribes cytosine to guanine" do
+    assert RnaTranscription.to_rna('C') == 'G'
+  end
+
+  # @tag :pending
+  test "transcribes thymidine to adenine" do
+    assert RnaTranscription.to_rna('T') == 'A'
+  end
+
+  # @tag :pending
+  test "transcribes adenine to uracil" do
+    assert RnaTranscription.to_rna('A') == 'U'
+  end
+
+  # @tag :pending
+  test "it transcribes all dna nucleotides to rna equivalents" do
+    assert RnaTranscription.to_rna('ACGTGGTCTTAA') == 'UGCACCAGAAUU'
+  end
+end
diff --git a/elixir/rna-transcription/test/test_helper.exs b/elixir/rna-transcription/test/test_helper.exs
new file mode 100644
index 0000000..35fc5bf
--- /dev/null
+++ b/elixir/rna-transcription/test/test_helper.exs
@@ -0,0 +1,2 @@
+ExUnit.start()
+ExUnit.configure(exclude: :pending, trace: true)