Added tests for 'displayContent' function

Programming Basics/Repetition with while/Exercise 1/src/Task.kt

@@ -0,0 +1,18 @@
+package repetitionwithwhile1
+
+fun displayContent(s: String) {
+  var i = 0
+  while (i < s.length) {
+    println(s[i])
+    i++
+  }
+}
+
+fun main() {
+  displayContent("abc")
+}
+/* Expected output:
+a
+b
+c
+*/

Programming Basics/Repetition with while/Exercise 1/task-info.yaml

@@ -0,0 +1,6 @@
+type: edu
+files:
+- name: src/Task.kt
+  visible: true
+- name: test/Tests.kt
+  visible: false

Programming Basics/Repetition with while/Exercise 1/task.md

@@ -0,0 +1,4 @@
+## Repetition with `while` (#2)
+
+Using a `while` loop, write a function that takes a `String` argument and
+displays each character on its own line.

Programming Basics/Repetition with while/Exercise 1/test/Tests.kt

@@ -0,0 +1,23 @@
+package repetitionwithwhile1
+
+import org.junit.Test
+import util.checkSystemOutput
+import util.runAndGetSystemOutput
+
+class TestDisplayContent {
+    private fun testInput(s: String) {
+        val output = runAndGetSystemOutput {
+            displayContent(s)
+        }
+        val expected = s.toList().joinToString("\n")
+        checkSystemOutput("""Wrong output for 'displayContent("$s")'""",
+          expected, output)
+    }
+
+    @Test
+    fun testDisplayContent() {
+        testInput("abc")
+        testInput("Kotlin")
+        testInput("Hi! I'm a String")
+    }
+}

Programming Basics/Repetition with while/lesson-info.yaml

@@ -1,5 +1,6 @@
 content:
 - Examples
+- Exercise 1
 - Exercise 2
 - Exercise 3
 - Exercise 4