test: adding ExchangeTest

src/test/java/millions/ExchangeTest.java

@@ -2,4 +2,82 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
-class ExchangeTest {}
+import java.math.BigDecimal;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class ExchangeTest {
+  @Test
+  public void testGetters() {
+    Stock s1 = new Stock("PEAR", "Pear Inc.", BigDecimal.valueOf(300));
+    Stock s2 = new Stock("DOGL", "DOOGLE Inc.", BigDecimal.valueOf(200.00));
+    Stock s3 = new Stock("MSFT", "EpsteinSoft Inc.", BigDecimal.valueOf(0.02));
+
+    Exchange exchange = new Exchange("exchange", List.of(s1, s2));
+
+    assertFalse(exchange.hasStock("MSFT"));
+    assertTrue(exchange.getStock("DOGL").equals(s2));
+    assertNull(exchange.getStock("XYZ"));
+    assertTrue(exchange.findStocks("Amozon").isEmpty());
+
+    assertTrue(exchange.hasStock("DOGL"));
+    assertFalse(exchange.findStocks("Pear").isEmpty());
+    assertFalse(exchange.findStocks("PE").isEmpty());
+
+    assertTrue(exchange.findStocks("Inc").size() == 2);
+  }
+
+  @Test
+  public void happyPath() {
+    Stock s1 = new Stock("PEAR", "Pear Inc.", BigDecimal.valueOf(300));
+    Stock s2 = new Stock("DOGL", "DOOGLE Inc.", BigDecimal.valueOf(200.00));
+    Stock s3 = new Stock("MSFT", "EpsteinSoft Inc.", BigDecimal.valueOf(0.02));
+
+    Exchange exchange = new Exchange("exchange", List.of(s1, s2, s3));
+    Player player = new Player("name", BigDecimal.valueOf(1000));
+
+    BigDecimal previousMoney = player.getMoney();
+    exchange.buy("PEAR", player, 2);
+    assertTrue(previousMoney.compareTo(player.getMoney()) > 0);
+
+    BigDecimal previousPrice = s1.getSalesPrice();
+    exchange.advance();
+    assertFalse(previousPrice.equals(s1.getSalesPrice()));
+
+    Share share = player.getPortfolio().getShares().getFirst();
+
+    previousMoney = player.getMoney();
+    exchange.sell(share, player);
+    assertTrue(previousMoney.compareTo(player.getMoney()) < 0);
+    assertTrue(player.getPortfolio().getShares().isEmpty());
+  }
+
+  @Test
+  public void testNullsAndInvalid() {
+    Stock s1 = new Stock("MSFT", "EpsteinSoft Inc.", BigDecimal.valueOf(0.02));
+
+    Exchange exchange = new Exchange("exchange", List.of(s1));
+    Player player = new Player("name", BigDecimal.valueOf(1000));
+
+    Share unownedShare = new Share(s1, BigDecimal.valueOf(1), s1.getSalesPrice());
+    assertThrows(IllegalStateException.class, () -> exchange.sell(unownedShare, player));
+
+    Player noMoney = new Player("nomoney", BigDecimal.valueOf(0));
+    assertThrows(IllegalStateException.class, () -> exchange.buy("MSFT", noMoney, 1));
+
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> new Exchange("", List.of(new Stock("PEAR", "Pear Inc.", BigDecimal.valueOf(300)))));
+
+    assertThrows(
+        IllegalArgumentException.class,
+        () -> new Exchange(null, List.of(new Stock("PEAR", "Pear Inc.", BigDecimal.valueOf(300)))));
+
+    assertThrows(IllegalArgumentException.class, () -> exchange.buy("DOGL", player, 2));
+
+    assertThrows(IllegalArgumentException.class, () -> exchange.buy("DOGL", player, -2));
+
+    assertThrows(
+        IllegalArgumentException.class, () -> exchange.buy("DOGL", player, BigDecimal.valueOf(-2)));
+  }
+}