Added exercise raindrops

config.json

@@ -20,7 +20,8 @@
     "scrabble-score",
     "roman-numerals",
     "binary",
-    "prime-factors"
+    "prime-factors",
+    "raindrops"
   ],
   "deprecated": [
   ],

raindrops/build.gradle

@@ -0,0 +1,11 @@
+apply plugin: "java"
+apply plugin: "eclipse"
+apply plugin: "idea"
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  testCompile "junit:junit:4.10"
+}

raindrops/example.java

@@ -0,0 +1,24 @@
+public class Raindrops {
+
+    public static String convert(int number) {
+        String result = "";
+
+        if (number % 3 == 0) {
+            result += "Pling";
+        }
+
+        if (number % 5 == 0) {
+            result += "Plang";
+        }
+
+        if (number % 7 == 0) {
+            result += "Plong";
+        }
+
+        if (result == null || result.isEmpty()) {
+            result = Integer.toString(number);
+        }
+
+        return result;
+    }
+}

raindrops/src/main/java/Raindrops.java

@@ -0,0 +1,2 @@
+public class Raindrops {
+}

raindrops/src/test/java/RaindropsTest.java

@@ -0,0 +1,57 @@
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Parameterized.class)
+public class RaindropsTest {
+
+    private int input;
+    private String expectedOutput;
+
+    @Parameters
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][]{
+                // Non-primes
+                {1, "1"},
+                {52, "52"},
+                {12121, "12121"},
+
+                // Numbers with 3 as a prime factor
+                {3, "Pling"},
+                {6, "Pling"},
+                {9, "Pling"},
+
+                // Numbers with 5 as a prime factor
+                {5, "Plang"},
+                {10, "Plang"},
+                {25, "Plang"},
+
+                // Numbers with 7 as a prime factor
+                {7, "Plong"},
+                {14, "Plong"},
+                {49, "Plong"},
+
+                // Numbers with multiple activating prime factors
+                {15, "PlingPlang"},
+                {21, "PlingPlong"},
+                {35, "PlangPlong"},
+                {105, "PlingPlangPlong"},
+        });
+    }
+
+    public RaindropsTest(int input, String expectedOutput) {
+        this.input = input;
+        this.expectedOutput = expectedOutput;
+    }
+
+    @Test
+    public void test() {
+        assertEquals(expectedOutput, Raindrops.convert(input));
+    }
+}