Add resistor-color-duo (#703)

* Add resistor-color-duo

* Apply code review for COLORS

Co-authored-by: Colin Caine <cmcaine@gmail.com>

* Update example.jl

* Use tuple in example.jl

* Update exercises/practice/resistor-color-duo/runtests.jl

---------

Co-authored-by: Colin Caine <cmcaine@gmail.com>
Co-authored-by: Erik Schierboom <erik_schierboom@hotmail.com>

config.json

@@ -691,6 +691,14 @@
           "unicode"
         ]
       },
+      {
+        "slug": "resistor-color-duo",
+        "name": "Resistor Color Duo",
+        "uuid": "c71c65c4-0572-4dd6-b864-317486821e54",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "resistor-color",
         "name": "Resistor Color",

exercises/practice/resistor-color-duo/.docs/instructions.md

@@ -0,0 +1,33 @@
+# Instructions
+
+If you want to build something using a Raspberry Pi, you'll probably use _resistors_.
+For this exercise, you need to know two things about them:
+
+- Each resistor has a resistance value.
+- Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.
+
+To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values.
+Each band has a position and a numeric value.
+
+The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
+For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.
+
+In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
+The program will take color names as input and output a two digit number, even if the input is more than two colors!
+
+The band colors are encoded as follows:
+
+- Black: 0
+- Brown: 1
+- Red: 2
+- Orange: 3
+- Yellow: 4
+- Green: 5
+- Blue: 6
+- Violet: 7
+- Grey: 8
+- White: 9
+
+From the example above:
+brown-green should return 15
+brown-green-violet should return 15 too, ignoring the third color.

exercises/practice/resistor-color-duo/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "resistor-color-duo.jl"
+    ],
+    "test": [
+      "runtests.jl"
+    ],
+    "example": [
+      ".meta/example.jl"
+    ]
+  },
+  "blurb": "Convert color codes, as used on resistors, to a numeric value.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1464"
+}

exercises/practice/resistor-color-duo/.meta/example.jl

@@ -0,0 +1,23 @@
+const COLORS = (
+    "black",
+    "brown",
+    "red",
+    "orange",
+    "yellow",
+    "green",
+    "blue",
+    "violet",
+    "grey",
+    "white"
+)
+
+function colorcode(colors)
+    tens = value(colors[1])
+    ones = value(colors[2])
+
+    tens * 10 + ones
+end
+
+function value(color)
+    findfirst(==(color), COLORS) - 1
+end

exercises/practice/resistor-color-duo/.meta/tests.toml

@@ -0,0 +1,31 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[ce11995a-5b93-4950-a5e9-93423693b2fc]
+description = "Brown and black"
+
+[7bf82f7a-af23-48ba-a97d-38d59406a920]
+description = "Blue and grey"
+
+[f1886361-fdfd-4693-acf8-46726fe24e0c]
+description = "Yellow and violet"
+
+[b7a6cbd2-ae3c-470a-93eb-56670b305640]
+description = "White and red"
+
+[77a8293d-2a83-4016-b1af-991acc12b9fe]
+description = "Orange and orange"
+
+[0c4fb44f-db7c-4d03-afa8-054350f156a8]
+description = "Ignore additional colors"
+
+[4a8ceec5-0ab4-4904-88a4-daf953a5e818]
+description = "Black and brown, one-digit"

exercises/practice/resistor-color-duo/resistor-color-duo.jl

@@ -0,0 +1,3 @@
+function colorcode(colors)
+
+end

exercises/practice/resistor-color-duo/runtests.jl

@@ -0,0 +1,33 @@
+using Test
+
+include("resistor-color-duo.jl")
+
+@testset verbose = true "tests" begin
+    @testset "Brown and black" begin
+        @test colorcode(["brown", "black"]) == 10
+    end
+
+    @testset "Blue and grey" begin
+        @test colorcode(["blue", "grey"]) == 68
+    end
+
+    @testset "Yellow and violet" begin
+        @test colorcode(["yellow", "violet"]) == 47
+    end
+
+    @testset "White and red" begin
+        @test colorcode(["white", "red"]) == 92
+    end
+
+    @testset "Orange and orange" begin
+        @test colorcode(["orange", "orange"]) == 33
+    end
+
+    @testset "Ignore additional colors" begin
+        @test colorcode(["green", "brown", "orange"]) == 51
+    end
+
+    @testset "Black and brown, one digit" begin
+        @test colorcode(["black", "brown"]) == 1
+    end
+end