fixes KT-2091 allowing fold() and foldRight() to take different types of initial value and return the same typed result

2012-09-21 16:31:04 +01:00
parent e129b43a7c
commit be44702145
12 changed files with 41 additions and 22 deletions
@@ -135,6 +135,18 @@ class CollectionTest {
        }
    }

+    test fun foldWithDifferentTypes() {
+        expect(7) {
+            val numbers = arrayList("a", "ab", "abc")
+            numbers.fold(1){ a, b -> a + b.size}
+        }
+
+        expect("1234") {
+            val numbers = arrayList(1, 2, 3, 4)
+            numbers.fold(""){ a, b -> a + b}
+        }
+    }
+
    test fun foldWithNonCommutativeOperation() {
        expect(1) {
            val numbers = arrayList(1, 2, 3)
@@ -149,6 +161,13 @@ class CollectionTest {
        }
    }

+    test fun foldRightWithDifferentTypes() {
+        expect("1234") {
+            val numbers = arrayList(1, 2, 3, 4)
+            numbers.foldRight(""){ a, b -> "" + a + b}
+        }
+    }
+
    test fun foldRightWithNonCommutativeOperation() {
        expect(-5) {
            val numbers = arrayList(1, 2, 3)