Moved tests over to Kotlin. (#1428)

app/src/test/kotlin/fr/free/nrw/commons/FileUtilsTest.kt

@@ -0,0 +1,33 @@
+package fr.free.nrw.commons
+
+import fr.free.nrw.commons.upload.FileUtils
+import org.junit.Assert.assertEquals
+import org.junit.Test
+import java.io.*
+
+class FileUtilsTest {
+    @Test
+    fun copiedFileIsIdenticalToSource() {
+        val source = File.createTempFile("temp", "")
+        val dest = File.createTempFile("temp", "")
+        writeToFile(source, "Hello, World")
+
+        FileUtils.copy(FileInputStream(source), FileOutputStream(dest))
+
+        assertEquals(getString(source), getString(dest))
+    }
+
+    private fun writeToFile(file: File, s: String) {
+        val buf = BufferedOutputStream(FileOutputStream(file))
+        buf.write(s.toByteArray())
+        buf.close()
+    }
+
+    private fun getString(file: File): String {
+        val bytes = ByteArray(file.length().toInt())
+        val buf = BufferedInputStream(FileInputStream(file))
+        buf.read(bytes, 0, bytes.size)
+        buf.close()
+        return String(bytes)
+    }
+}