Add resistor-color exercise (#702)

* Add resistor-color exercise

* Use a tuple in the example

* Allow other collections for colors()

---------

Co-authored-by: Colin Caine <[email protected]>

config.json

@@ -691,6 +691,14 @@
           "unicode"
         ]
       },
+      {
+        "slug": "resistor-color",
+        "name": "Resistor Color",
+        "uuid": "ef7e22db-1f66-4d44-87f9-23d97f794628",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
+      },
       {
         "slug": "resistor-color-trio",
         "name": "Resistor Color Trio",

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

@@ -0,0 +1,39 @@
+# 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.
+
+In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands.
+
+These 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
+
+The goal of this exercise is to create a way:
+
+- to look up the numerical value associated with a particular color band
+- to list the different band colors
+
+Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array:
+Better Be Right Or Your Great Big Values Go Wrong.
+
+More information on the color encoding of resistors can be found in the [Electronic color code Wikipedia article][e-color-code].
+
+[e-color-code]: https://en.wikipedia.org/wiki/Electronic_color_code

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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "resistor-color.jl"
+    ],
+    "test": [
+      "runtests.jl"
+    ],
+    "example": [
+      ".meta/example.jl"
+    ]
+  },
+  "blurb": "Convert a resistor band's color to its numeric representation.",
+  "source": "Maud de Vries, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/1458"
+}

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

@@ -0,0 +1,20 @@
+const COLORS = (
+    "black",
+    "brown",
+    "red",
+    "orange",
+    "yellow",
+    "green",
+    "blue",
+    "violet",
+    "grey",
+    "white"
+)
+
+function colorcode(color)
+    findfirst(==(color), COLORS) - 1
+end
+
+function colors()
+    COLORS
+end

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

@@ -0,0 +1,22 @@
+# 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.
+
+[49eb31c5-10a8-4180-9f7f-fea632ab87ef]
+description = "Color codes -> Black"
+
+[0a4df94b-92da-4579-a907-65040ce0b3fc]
+description = "Color codes -> White"
+
+[5f81608d-f36f-4190-8084-f45116b6f380]
+description = "Color codes -> Orange"
+
+[581d68fa-f968-4be2-9f9d-880f2fb73cf7]
+description = "Colors"

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

@@ -0,0 +1,7 @@
+function colorcode(color)
+
+end
+
+function colors()
+
+end

exercises/practice/resistor-color/runtests.jl

@@ -0,0 +1,33 @@
+using Test
+
+include("resistor-color.jl")
+
+@testset verbose = true "Resistor Color" begin
+    @testset "Black" begin
+        @test colorcode("black") == 0
+    end
+
+    @testset "White" begin
+        @test colorcode("white") == 9
+    end
+
+    @testset "Orange" begin
+        @test colorcode("orange") == 3
+    end
+
+    @testset "Colors" begin
+        expected_colors = [
+            "black",
+            "brown",
+            "red",
+            "orange",
+            "yellow",
+            "green",
+            "blue",
+            "violet",
+            "grey",
+            "white"
+        ]
+        @test all(colors() .== expected_colors)
+    end
+end