Finished issue get-gainers&losers

src/main/java/edu/ntnu/idi/idatt/Exchange.java

@@ -8,6 +8,7 @@
 
 import java.math.BigDecimal;
 import java.util.*;
+import java.util.stream.Collectors;
 
 /**
  * Exchange class
@@ -99,6 +100,44 @@ public List<Stock> findStocks(String searchTerm) {
     return stocksFound;
   }
 
+  /**
+   * Method for obtaining gainers
+   *
+   * <p>
+   * Returns the stocks that have done it the best
+   * in the latest week.
+   * </p>
+   *
+   * @param limit - Amount of stocks to be returned.
+   * @return A list of stocks sorted in declining order.
+   */
+  public List<Stock> getGainers(int limit) {
+    return stockMap.values().stream()
+        .filter(stock -> stock.getLatestPriceChange().compareTo(BigDecimal.ZERO) > 0)
+        .sorted(Comparator.comparing(Stock::getLatestPriceChange).reversed())
+        .limit(limit)
+        .toList();
+  }
+
+  /**
+   * Method for obtaining losers
+   *
+   * <p>
+   * Returns the stocks that have done it the worst
+   * in value in the latest week.
+   * </p>
+   *
+   * @param limit - Amount of stocks to be returned.
+   * @return A list of stocks sorted in inclining order.
+   */
+  public List<Stock> getLosers(int limit) {
+    return stockMap.values().stream()
+        .filter(stock -> stock.getLatestPriceChange().compareTo(BigDecimal.ZERO) < 0)
+        .sorted(Comparator.comparing(Stock::getLatestPriceChange))
+        .limit(limit)
+        .toList();
+  }
+
   /**
    * Method to allow a player to buy a stock.
    *

src/main/java/edu/ntnu/idi/idatt/marked/Stock.java

@@ -87,7 +87,7 @@ public BigDecimal getLatestPriceChange() {
       return BigDecimal.ZERO;
     }
     int size = prices.size();
-    return prices.get(size - 1).min(prices.get(size - 2));
+    return prices.get(size - 1).subtract(prices.get(size - 2));
   }
 
   /**

src/test/java/edu/ntnu/idi/idatt/ExchangeTest.java

@@ -120,6 +120,24 @@ void PTAdvance() {
 
   }
 
+  /**
+   * Test for obtaining the gainers and loosers.
+   */
+  @Test
+  void PTgetGainers_Losers() {
+    // Simulate price change
+    stocks.get(0).addNewSalesPrice(new BigDecimal("4333"));
+    stocks.get(1).addNewSalesPrice(new BigDecimal("50"));
+    stocks.get(2).addNewSalesPrice(new BigDecimal("3"));
+    stocks.get(3).addNewSalesPrice(new BigDecimal("800"));
+
+    assertEquals(2, exchange.getGainers(2).size());
+    assertEquals(2, exchange.getLosers(2).size());
+
+    assertEquals(List.of(stocks.get(0)), exchange.getGainers(1));
+    assertEquals(List.of(stocks.get(2)), exchange.getLosers(1));
+  }
+
   /**
    * Negative tests for stock-related methods.
    *

src/test/java/edu/ntnu/idi/idatt/marked/StockTest.java

@@ -36,7 +36,7 @@ void PTgetPrices() {
     assertEquals(prices, stock.getHistoricalPrices());
     assertEquals(new BigDecimal("39.5"), stock.getLowestPrice());
     assertEquals(new BigDecimal("51.2"), stock.getHighestPrice());
-    assertEquals(new BigDecimal("43.4").min(new BigDecimal("51.2")), stock.getLatestPriceChange());
+    assertEquals(new BigDecimal("43.4").subtract(new BigDecimal("51.2")), stock.getLatestPriceChange());
   }
 
   @Test