test: adding TransactionArchiveTest

src/test/java/millions/TransactionArchiveTest.java

@@ -2,4 +2,45 @@
 
 import static org.junit.jupiter.api.Assertions.*;
 
-class TransactionArchiveTest {}
+import java.math.BigDecimal;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class TransactionArchiveTest {
+
+  TransactionArchive archive;
+  Purchase purchase;
+  Sale sale;
+
+  @BeforeEach
+  public void setUp() {
+    archive = new TransactionArchive();
+    Stock stock = new Stock("SUS", "Samsung", BigDecimal.valueOf(10));
+    Share share = new Share(stock, 2, BigDecimal.valueOf(10));
+    purchase = new Purchase(share, 1);
+    sale = new Sale(share, 2);
+  }
+
+  @Test
+  public void testHappyPath() {
+    assertTrue(archive.isEmpty());
+    archive.add(purchase);
+    assertFalse(archive.isEmpty());
+  }
+
+  @Test
+  public void testNullsAndInvalid() {
+    archive.add(purchase);
+    assertFalse(archive.add(purchase));
+  }
+
+  @Test
+  public void testGetters() {
+    archive.add(purchase);
+    archive.add(sale);
+    assertEquals(List.of(purchase), archive.getPurchases(1));
+    assertEquals(List.of(sale), archive.getSales(2));
+    assertEquals(2, archive.countDistinctWeeks());
+  }
+}