fix(backend): add @Builder.Default to entity fields and add unit test suite

backend/src/main/java/com/rit/portal/entity/CommunityAnswer.java

@@ -30,11 +30,14 @@ public class CommunityAnswer {
     private String author;
 
     @Column(name = "upvotes")
+    @Builder.Default
     private Integer upvotes = 0;
 
     @Column(name = "is_accepted")
+    @Builder.Default
     private Boolean isAccepted = false;
 
     @Column(name = "created_at")
+    @Builder.Default
     private LocalDateTime createdAt = LocalDateTime.now();
 }

backend/src/main/java/com/rit/portal/entity/CommunityQuestion.java

@@ -29,15 +29,19 @@ public class CommunityQuestion {
     private String author;
 
     @Column(name = "upvotes")
+    @Builder.Default
     private Integer upvotes = 0;
 
     @Column(name = "tags", columnDefinition = "text[]")
+    @Builder.Default
     private List<String> tags = new ArrayList<>();
 
     @Column(name = "is_answered")
+    @Builder.Default
     private Boolean isAnswered = false;
 
     @Column(name = "created_at")
+    @Builder.Default
     private LocalDateTime createdAt = LocalDateTime.now();
 
     @OneToMany(mappedBy = "question", cascade = CascadeType.ALL, fetch = FetchType.EAGER)

backend/src/main/java/com/rit/portal/entity/NotePyq.java

@@ -39,8 +39,10 @@ public class NotePyq {
     private String fileSize;
 
     @Column(name = "downloads_count")
+    @Builder.Default
     private Integer downloadsCount = 0;
 
     @Column(name = "uploaded_at")
+    @Builder.Default
     private LocalDateTime uploadedAt = LocalDateTime.now();
 }

backend/src/test/java/com/rit/portal/BusLocationServiceTest.java

@@ -0,0 +1,58 @@
+package com.rit.portal;
+
+import com.rit.portal.model.BusLocation;
+import com.rit.portal.service.BusLocationService;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class BusLocationServiceTest {
+
+    private BusLocationService busLocationService;
+
+    @BeforeEach
+    void setUp() {
+        busLocationService = new BusLocationService();
+    }
+
+    @Test
+    void testUpdateAndGetLocation() {
+        busLocationService.updateLocation("24A", 13.0827, 80.2707);
+
+        BusLocation loc = busLocationService.getLocation("24A");
+        assertNotNull(loc);
+        assertEquals("24A", loc.getRouteNumber());
+        assertEquals(13.0827, loc.getLatitude());
+        assertEquals(80.2707, loc.getLongitude());
+        assertFalse(loc.isStopped());
+        assertNotNull(loc.getLastUpdated());
+    }
+
+    @Test
+    void testStopLocation() {
+        busLocationService.updateLocation("15B", 12.9716, 77.5946);
+        busLocationService.stopLocation("15B");
+
+        BusLocation loc = busLocationService.getLocation("15B");
+        assertNotNull(loc);
+        assertTrue(loc.isStopped());
+    }
+
+    @Test
+    void testGetNonExistentLocationReturnsNull() {
+        BusLocation loc = busLocationService.getLocation("NON_EXISTENT");
+        assertNull(loc);
+    }
+
+    @Test
+    void testGetActiveLocations() {
+        busLocationService.updateLocation("R1", 13.0, 80.0);
+        busLocationService.updateLocation("R2", 13.1, 80.1);
+
+        List<BusLocation> active = busLocationService.getActiveLocations();
+        assertEquals(2, active.size());
+    }
+}

backend/src/test/java/com/rit/portal/EntityMappingTest.java

@@ -0,0 +1,60 @@
+package com.rit.portal;
+
+import com.rit.portal.entity.CommunityAnswer;
+import com.rit.portal.entity.CommunityQuestion;
+import com.rit.portal.entity.NotePyq;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDateTime;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class EntityMappingTest {
+
+    @Test
+    void testNotePyqBuilderDefaults() {
+        NotePyq note = NotePyq.builder()
+                .title("Data Structures Notes")
+                .subject("Data Structures")
+                .department("CSE")
+                .semester(3)
+                .fileType("notes")
+                .downloadUrl("https://example.com/ds.pdf")
+                .fileSize("2.4 MB")
+                .build();
+
+        assertNotNull(note);
+        assertEquals(0, note.getDownloadsCount());
+        assertNotNull(note.getUploadedAt());
+        assertTrue(note.getUploadedAt().isBefore(LocalDateTime.now().plusSeconds(1)));
+    }
+
+    @Test
+    void testCommunityQuestionBuilderDefaults() {
+        CommunityQuestion question = CommunityQuestion.builder()
+                .title("How to prepare for CAT-1?")
+                .body("Looking for reference materials and past questions.")
+                .author("Student123")
+                .build();
+
+        assertNotNull(question);
+        assertEquals(0, question.getUpvotes());
+        assertFalse(question.getIsAnswered());
+        assertNotNull(question.getTags());
+        assertNotNull(question.getAnswers());
+        assertNotNull(question.getCreatedAt());
+    }
+
+    @Test
+    void testCommunityAnswerBuilderDefaults() {
+        CommunityAnswer answer = CommunityAnswer.builder()
+                .body("Focus on Unit 1 and Unit 2 standard questions.")
+                .author("Senior456")
+                .build();
+
+        assertNotNull(answer);
+        assertEquals(0, answer.getUpvotes());
+        assertFalse(answer.getIsAccepted());
+        assertNotNull(answer.getCreatedAt());
+    }
+}