added second and third test case for setDevices() & productive code

src/main/java/BordComputer.java

@@ -29,7 +29,9 @@ public class BordComputer {
 
     public void setDevices() throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException, ClassNotFoundException {
         Class<?> c;
-        c= Class.forName(deviceNames[0]);
-        installedDevices[0] = (Device) c.getConstructor().newInstance();
+        for(int i = 0;i < deviceNames.length; i++) {
+            c = Class.forName(deviceNames[i]);
+            installedDevices[i] = (Device) c.getConstructor().newInstance();
+        }
     }
 }

src/test/java/BordComputerTest.java

@@ -50,8 +50,11 @@ class BordComputerTest {
 
     @ParameterizedTest
     @MethodSource("setDevicesOptions")
-    void setDevicesTest(String testName, BordComputer testBc) {
-        Device dev = testBc.installedDevices[0];
+    void setDevicesTest(String testName, BordComputer testBc, String testTyp) {
+        Device dev = null;
+        if(testTyp.equals("0")) dev = testBc.installedDevices[0];
+        if(testTyp.equals("1")) dev = testBc.installedDevices[1];
+        if(testTyp.equals("2")) dev = testBc.installedDevices[2];
         assertThat(dev).describedAs(testName).isNotEqualTo(null);
     }
 
@@ -60,8 +63,9 @@ class BordComputerTest {
         bc.readConfig();
         bc.setDevices();
         return Stream.of(
-                Arguments.of("Test if installedDevices[0] is not null", bc)
-
+                Arguments.of("Test if installedDevices[0] is not null", bc, "0"),
+                Arguments.of("Test if installedDevices[1] is not null", bc, "1"),
+                Arguments.of("Test if installedDevices[2] is not null", bc, "2")
         );
     }
     public int fileReaderCount() {