diff --git a/src/test/java/edu/group5/app/model/donation/DonationRepositoryTest.java b/src/test/java/edu/group5/app/model/donation/DonationRepositoryTest.java
index e06a350..b55ef57 100644
--- a/src/test/java/edu/group5/app/model/donation/DonationRepositoryTest.java
+++ b/src/test/java/edu/group5/app/model/donation/DonationRepositoryTest.java
@@ -1,4 +1,188 @@
 package edu.group5.app.model.donation;
 
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.math.BigDecimal;
+import java.sql.Timestamp;
+import java.util.HashMap;
+
+import static org.junit.jupiter.api.Assertions.*;
+
 public class DonationRepositoryTest {
+  private DonationRepository repo;
+  private Timestamp now;
+  private Donation donation1;
+  private Donation donation2;
+  private Donation donation3;
+  private Donation donation4;
+
+  @BeforeEach
+  void setUp() {
+    repo = new DonationRepository(new HashMap<>());
+
+    Timestamp ts1 = Timestamp.valueOf("2025-01-01 10:00:00");
+    Timestamp ts2 = Timestamp.valueOf("2025-01-01 10:00:01");
+    now = new Timestamp(System.currentTimeMillis());
+
+    donation1 = new Donation(1, 102, 202, new BigDecimal("500.0"), ts1, "Card");
+    donation2 = new Donation(2, 102, 202, new BigDecimal("500.0"), ts2, "PayPal");
+    donation3 = new Donation(3, 103, 203, new BigDecimal("200.0"), now, "PayPal");
+    donation4 = new Donation(1, 101, 201, new BigDecimal("500.0"), now, "Card");
+
+
+  }
+  @Test
+  void testThrowsExceptionIfContentIsNull() {
+    IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class,
+        () -> new DonationRepository(null));
+    assertEquals("Content cannot be null", thrown.getMessage());
+  }
+
+  @Test
+  void testAddDonation() {
+    assertTrue(repo.addDonation(donation1));
+    assertEquals(1, repo.getContent().size());
+
+    assertTrue(repo.addDonation(donation3));
+    assertEquals(2, repo.getContent().size());
+  }
+  @Test
+  void testAddDonationWithDuplicateId() {
+    assertTrue(repo.addDonation(donation1));
+    assertFalse(repo.addDonation(donation4));
+    assertEquals(1, repo.getContent().size());
+  }
+  @Test
+  void testAddNullDonation() {
+    IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class,
+        () -> repo.addDonation(null));
+    assertEquals("Donation cannot be null",thrown.getMessage());
+  }
+
+  @Test
+  void testSortByDate() {
+    repo.addDonation(donation3);
+    repo.addDonation(donation1);
+    repo.addDonation(donation2);
+
+    HashMap<Integer, Donation> sorted = repo.sortByDate();
+
+    Integer[] keys = sorted.keySet().toArray(new Integer[0]);
+    assertEquals(1, keys[0]);
+    assertEquals(2, keys[1]);
+    assertEquals(3, keys[2]);
+
+  }
+  @Test
+  void testSortByDateWithSameDate() {
+
+    repo.addDonation(donation3);
+    repo.addDonation(donation4);
+
+    HashMap<Integer, Donation> sorted = repo.sortByDate();
+
+    assertEquals(2, sorted.size());
+    assertTrue(sorted.containsKey(1));
+    assertTrue(sorted.containsKey(3));
+  }
+  @Test
+  void testSortByDateWithSameDonation() {
+    Timestamp sameDate = Timestamp.valueOf("2025-01-01 10:00:00");
+
+    Donation d1 = new Donation(1, 101, 201,
+        new BigDecimal("500.0"), sameDate, "Card");
+
+    repo.addDonation(d1);
+    repo.addDonation(donation4);
+
+    HashMap<Integer, Donation> sorted = repo.sortByDate();
+
+    assertEquals(1, sorted.size());
+    assertTrue(sorted.containsKey(1));
+    assertFalse(sorted.containsKey(2));
+  }
+  @Test
+  void TestSortByAmountTest() {
+    repo.addDonation(donation2);
+    repo.addDonation(donation3);
+
+    HashMap<Integer, Donation> sorted = repo.sortByAmount();
+    Integer[] keys = sorted.keySet().toArray(new Integer[0]);
+
+    assertEquals(3, keys[0]);
+    assertEquals(2, keys[1]);
+
+
+  }
+  @Test
+  void testSortByAmountWithSameAmount() {
+    repo.addDonation(donation1);
+    repo.addDonation(donation2);
+
+    HashMap<Integer, Donation> sorted = repo.sortByAmount();
+
+    assertEquals(2, sorted.size());
+    assertTrue(sorted.containsKey(1));
+    assertTrue(sorted.containsKey(2));
+  }
+  @Test
+  void testSortByAmountWithSameDonation() {
+
+    Donation d1 = new Donation(1, 101, 201,
+        new BigDecimal("500.0"), now, "Card");
+
+    repo.addDonation(d1);
+    repo.addDonation(donation4);
+
+    HashMap<Integer, Donation> sorted = repo.sortByAmount();
+
+    assertEquals(1, sorted.size());
+    assertTrue(sorted.containsKey(1));
+    assertFalse(sorted.containsKey(2));
+  }
+  @Test
+  void testFilterByOrganization() {
+    repo.addDonation(donation1);
+    repo.addDonation(donation2);
+
+    HashMap<Integer, Donation> filtered = repo.filterByOrganization(202);
+
+    assertEquals(2, filtered.size());
+    assertTrue(filtered.containsKey(1));
+    assertTrue(filtered.containsKey(2));
+    assertFalse(filtered.containsKey(3));
+  }
+  @Test
+  void testFilterByOrganizationNoMatch() {
+    repo.addDonation(donation1);
+    repo.addDonation(donation2);
+
+    HashMap<Integer, Donation> filtered = repo.filterByOrganization(999);
+
+    assertTrue(filtered.isEmpty());
+  }
+  @Test
+  void testThrowsExceptionWhenOrgNumberIsNegative() {
+    IllegalArgumentException thrown = assertThrows(IllegalArgumentException.class,
+        () -> repo.filterByOrganization(-1));
+    assertEquals("Organization number must be positive",thrown.getMessage());
+  }
+  @Test
+  void testFilterByOrganizationWithSameDonation() {
+    Timestamp sameDate = Timestamp.valueOf("2025-01-01 10:00:00");
+
+    Donation d1 = new Donation(1, 101, 201,
+        new BigDecimal("500.0"), sameDate, "Card");
+
+    repo.addDonation(d1);
+    repo.addDonation(donation4);
+
+    HashMap<Integer, Donation> sorted = repo.filterByOrganization(201);
+
+    assertEquals(1, sorted.size());
+    assertTrue(sorted.containsKey(1));
+    assertFalse(sorted.containsKey(2));
+  }
+
 }