Add exercise: raindrops (JuliaLang#20)

config.json

@@ -57,6 +57,15 @@
 				"mathematics"
       ]
     },
+    {
+      "slug": "raindrops",
+      "difficulty": 1,
+      "topics": [
+        "control-flow (loops)",
+        "arrays",
+        "strings"
+      ]
+    },
     {
       "slug": "scrabble-score",
       "difficulty": 1,

exercises/raindrops/example.jl

@@ -0,0 +1,16 @@
+# If the number has 3 as a factor, output 'Pling'.
+# If the number has 5 as a factor, output 'Plang'.
+# If the number has 7 as a factor, output 'Plong'.
+# If the number does not have 3, 5, or 7 as a factor, just pass the number's digits straight through.
+
+function raindrops(number::Int)
+  drops = []
+  number % 3 == 0 && push!(drops, "Pling")
+  number % 5 == 0 && push!(drops, "Plang")
+  number % 7 == 0 && push!(drops, "Plong")
+  if size(drops, 1) == 0
+    repr(number)
+  else
+    join(drops)
+  end
+end

exercises/raindrops/raindrops.jl

@@ -0,0 +1,3 @@
+function raindrops(number::Int)
+
+end

exercises/raindrops/runtests.jl

@@ -0,0 +1,72 @@
+using Base.Test
+
+include("raindrops.jl")
+
+@testset "detect numbers" begin
+  @testset "the sound for 1 is 1" begin
+    @test raindrops(1) == "1"
+  end
+  @testset "2 to the power 3 does not make a raindrop sound as 3 is the exponent not the base" begin
+    @test raindrops(8) == "8"
+  end
+  @testset "the sound for 52 is 52" begin
+    @test raindrops(52) == "52"
+  end
+end
+
+@testset "detect pling" begin
+  @testset "the sound for 3 is Pling" begin
+    @test raindrops(3) == "Pling"
+  end
+  @testset "the sound for 6 is Pling as it has a factor 3" begin
+    @test raindrops(6) == "Pling"
+  end
+  @testset "the sound for 9 is Pling as it has a factor 3" begin
+    @test raindrops(9) == "Pling"
+  end
+  @testset "the sound for 27 is Pling as it has a factor 3" begin
+    @test raindrops(27) == "Pling"
+  end
+end
+
+@testset "detect plang" begin
+  @testset "the sound for 5 is Plang" begin
+    @test raindrops(5) == "Plang"
+  end
+  @testset "the sound for 10 is Plang as it has a factor 5" begin
+    @test raindrops(10) == "Plang"
+  end
+  @testset "the sound for 25 is Plang as it has a factor 5" begin
+    @test raindrops(25) == "Plang"
+  end
+  @testset "the sound for 3125 is Plang as it has a factor 5" begin
+    @test raindrops(3125) == "Plang"
+  end
+end
+
+@testset "detect plong" begin
+  @testset "the sound for 7 is Plong" begin
+    @test raindrops(7) == "Plong"
+  end
+  @testset "the sound for 14 is Plong as it has a factor of 7" begin
+    @test raindrops(14) == "Plong"
+  end
+  @testset "the sound for 49 is Plong as it has a factor 7" begin
+    @test raindrops(49) == "Plong"
+  end
+end
+
+@testset "detect multiple sounds" begin
+  @testset "the sound for 15 is PlingPlang as it has factors 3 and 5" begin
+    @test raindrops(15) == "PlingPlang"
+  end
+  @testset "the sound for 21 is PlingPlong as it has factors 3 and 7" begin
+    @test raindrops(21) == "PlingPlong"
+  end
+  @testset "the sound for 35 is PlangPlong as it has factors 5 and 7" begin
+    @test raindrops(35) == "PlangPlong"
+  end
+  @testset "the sound for 105 is PlingPlangPlong as it has factors 3, 5 and 7" begin
+    @test raindrops(105) == "PlingPlangPlong"
+  end
+end