IDE-151 Refactor Stopwatch.java to kotlin

catroid/src/androidTest/java/org/catrobat/catroid/test/utils/StopwatchTest.kt

@@ -0,0 +1,39 @@
+/*
+ * Catroid: An on-device visual programming system for Android devices
+ * Copyright (C) 2010-2023 The Catrobat Team
+ * (<http://developer.catrobat.org/credits>)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * An additional term exception under section 7 of the GNU Affero
+ * General Public License, version 3, is available at
+ * http://developer.catrobat.org/license_additional_term
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.catrobat.catroid.test.utils
+
+import junit.framework.TestCase.assertTrue
+import org.catrobat.catroid.utils.Stopwatch
+import org.junit.Test
+
+class StopwatchTest {
+    @Test
+    fun getElapsedMilliseconds() {
+        val stopwatch = Stopwatch()
+        stopwatch.start()
+        Thread.sleep(100L)
+        val elapsed = stopwatch.getElapsedMilliseconds()
+        assertTrue(elapsed in 100L..199)
+    }
+}

catroid/src/main/java/org/catrobat/catroid/utils/Stopwatch.java → catroid/src/main/java/org/catrobat/catroid/utils/Stopwatch.kt

@@ -1,6 +1,6 @@
 /*
  * Catroid: An on-device visual programming system for Android devices
- * Copyright (C) 2010-2022 The Catrobat Team
+ * Copyright (C) 2010-2023 The Catrobat Team
  * (<http://developer.catrobat.org/credits>)
  *
  * This program is free software: you can redistribute it and/or modify
@@ -20,17 +20,15 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-package org.catrobat.catroid.utils;
+package org.catrobat.catroid.utils
 
-public class Stopwatch {
+class Stopwatch {
+    private var start: Long = 0
+    fun start() {
+        start = System.currentTimeMillis()
+    }
 
-	private long start;
-
-	public void start() {
-		start = System.currentTimeMillis();
-	}
-
-	public long getElapsedMilliseconds() {
-		return (System.currentTimeMillis() - start);
-	}
+    fun getElapsedMilliseconds(): Long {
+        return System.currentTimeMillis() - start
+    }
 }