Introduce a FizzBuzz Interface

Author: dvberkel

src/main/kotlin/nl/fifthpostulate/FizzBuzz.kt

@@ -0,0 +1,5 @@
+package nl.fifthpostulate
+
+interface FizzBuzz {
+    fun of(n: Int): String
+}

src/main/kotlin/nl/fifthpostulate/standard/FizzBuzz.kt renamed to src/main/kotlin/nl/fifthpostulate/standard/Standard.kt

@@ -1,7 +1,9 @@
 package nl.fifthpostulate.standard
 
-class FizzBuzz {
-    fun of(n: Int): String {
+import nl.fifthpostulate.FizzBuzz
+
+class Standard: FizzBuzz {
+    override fun of(n: Int): String {
         if (n % 15 == 0) {
             return "FizzBuzz"
         }

src/test/kotlin/nl/fifthpostulate/standard/StandardTest.kt

@@ -1,5 +1,6 @@
 package nl.fifthpostulate.standard
 
+import nl.fifthpostulate.FizzBuzz
 import org.junit.jupiter.api.BeforeEach
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -9,7 +10,7 @@ class StandardTest {
 
     @BeforeEach
     fun createFizzBuzz() {
-        fizzbuzz = FizzBuzz()
+        fizzbuzz = Standard()
     }
 
     @Test