QuieterTest is implemented

src/test/java/device/usbPlayer/UsbPlayerTest.java

@@ -1,6 +1,11 @@
 package device.usbPlayer;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.util.stream.Stream;
 
 import static org.junit.jupiter.api.Assertions.*;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -9,7 +14,24 @@ class UsbPlayerTest {
 
     UsbPlayer up = new UsbPlayer();
 
+    @ParameterizedTest
+    @MethodSource("quieterOptions")
+    void quieterTest(String testName, UsbPlayer inputPlay, int expectedResult) {
+        int volumeNum = inputPlay.getLautstaerke();
+        assertThat(volumeNum).describedAs(testName).isEqualTo(expectedResult);
+    }
 
+    static Stream<Arguments> quieterOptions() {
+        UsbPlayer up1 = new UsbPlayer();
+        up1.quieter();
+        UsbPlayer up2 = new UsbPlayer();
+        up2.setLautstaerke(10);
+        up2.quieter();
+        return Stream.of(
+                Arguments.of("Volume must stay 0 ", up1, 0),
+                Arguments.of("Volume must be 9 ", up2, 9)
+        );
+    }
 
 /*
     @Test