Merge pull request #135 from npatarino/add_mapof_method_for_tuple2

Add mapOf method for Tuple2

kategory/src/main/kotlin/kategory/Maps.kt

@@ -0,0 +1,4 @@
+package kategory
+
+fun <K, V> mapOf(vararg tuple: Tuple2<K, V>): Map<K, V> =
+        if (tuple.isNotEmpty()) tuple.map { it.a to it.b }.toMap() else emptyMap()

kategory/src/test/kotlin/kategory/MapsTest.kt

@@ -0,0 +1,37 @@
+package kategory
+
+import io.kotlintest.KTestJUnitRunner
+import org.junit.Assert
+import org.junit.runner.RunWith
+
+@RunWith(KTestJUnitRunner::class)
+class MapsTest : UnitSpec() {
+
+    init {
+
+        "multiple instances with same values of Tuple2 and Pair should give the same map" {
+            val mapOfTuple = mapOf(Tuple2("one", 1), Tuple2("two", 2), Tuple2("three", 3))
+            val mapOfPair = mapOf("one" to 1, "two" to 2, "three" to 3)
+            Assert.assertEquals(mapOfPair, mapOfTuple)
+        }
+
+        "multiple instances with same values of Tuple2 and Pair in different order should give the same map" {
+            val mapOfTuple = mapOf(Tuple2("one", 1), Tuple2("two", 2), Tuple2("three", 3))
+            val mapOfPair = mapOf("two" to 2, "three" to 3, "one" to 1)
+            Assert.assertEquals(mapOfPair, mapOfTuple)
+        }
+
+        "different instances of Tuple2 and Pair should give a different maps" {
+            val mapOfTuple = mapOf(Tuple2("one", 1), Tuple2("two", 2), Tuple2("three", 3))
+            val mapOfPair = mapOf("four" to 4, "two" to 2, "three" to 3)
+            Assert.assertNotEquals(mapOfPair, mapOfTuple)
+        }
+
+        "an instance of Tuple2 should give the same map as the instance of Pair with same value" {
+            val mapOfTuple = mapOf(Tuple2("one", 1))
+            val mapOfPair = mapOf("one" to 1)
+            Assert.assertEquals(mapOfPair, mapOfTuple)
+        }
+
+    }
+}