Added tests for amazon data source

src/test/java/de/rwu/easydrop/api/client/AmazonProductDataSourceTest.java

@@ -188,4 +188,16 @@ class AmazonProductDataSourceTest {
         // Verify the exception message
         assertEquals("Couldn't fulfill Amazon API request", exception.getMessage());
     }
+
+    @Test
+    void getDataOrigin_ReturnsExpectedDataOrigin() {
+        String dataOrigin = demoDataSource.getDataOrigin();
+        assertEquals(demoDataOrigin, dataOrigin);
+    }
+
+    @Test
+    void getApiKey_ReturnsExpectedApiKey() {
+        String apiKey = demoDataSource.getApiKey();
+        assertEquals(demoApiKey, apiKey);
+    }
 }