test(backend): add happy-path test pyramid — repo, service, e2e

- TimeEntryRepositoryTest (@DataJpaTest): inserts entries across two weeks,
  asserts date-range query returns only the correct slice
- ReportServiceTest (@ExtendWith(MockitoExtension)): mocks repository,
  covers weekly aggregation, parseIsoWeekToMonday returning a Monday,
  and monthly breach detection (both time and cost thresholds)
- TimeEntryEndToEndTest (@SpringBootTest + MockMvc): POST a 90-min entry,
  GET /api/reports/weekly, assert weekTotalMinutes=90

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/src/test/java/com/example/app/report/ReportServiceTest.java

@@ -0,0 +1,63 @@
+package com.example.app.report;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.when;
+
+import com.example.app.report.ReportDtos.WeeklyReport;
+import com.example.app.time.TimeEntryRepository;
+import java.sql.Date;
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class ReportServiceTest {
+
+  @Mock TimeEntryRepository timeEntryRepository;
+  @InjectMocks ReportService reportService;
+
+  @Test
+  void weeklyReport_aggregatesDayTotalsCorrectly() {
+    LocalDate monday = ReportService.parseIsoWeekToMonday("2026-W20");
+    Object[] row = {Date.valueOf(monday), 120L, 9600L}; // 2h, 96.00 EUR
+
+    when(timeEntryRepository.aggregateByDay(anyLong(), any(), any())).thenReturn(List.of(row));
+
+    WeeklyReport report = reportService.weeklyReport(1L, "2026-W20");
+
+    assertThat(report.days()).hasSize(7);
+    assertThat(report.weekTotalMinutes()).isEqualTo(120);
+    assertThat(report.weekTotalCostCents()).isEqualTo(9600);
+    // first day has data, rest are zero
+    assertThat(report.days().get(0).totalMinutes()).isEqualTo(120);
+    assertThat(report.days().get(1).totalMinutes()).isEqualTo(0);
+  }
+
+  @Test
+  void parseIsoWeekToMonday_returnsCorrectMonday() {
+    // 2026-W01 should start on Monday 2025-12-29 (ISO week based year)
+    LocalDate monday = ReportService.parseIsoWeekToMonday("2026-W20");
+    assertThat(monday.getDayOfWeek().getValue()).isEqualTo(1); // Monday
+  }
+
+  @Test
+  void monthlyReport_marksBreachedProjects() {
+    // budget 60 minutes, logged 90 — breached
+    Object[] row = {1L, "Acme", 60, 100_00, 90L, 120_00L};
+    when(timeEntryRepository.aggregateByProjectForMonth(anyLong(), anyInt(), anyInt()))
+        .thenReturn(List.of(row));
+
+    var report = reportService.monthlyReport(1L, "2026-05");
+
+    assertThat(report.projects()).hasSize(1);
+    assertThat(report.projects().get(0).breached()).isTrue();
+    assertThat(report.projects().get(0).timeBudgetPct()).isGreaterThan(100.0);
+  }
+}

backend/src/test/java/com/example/app/time/TimeEntryEndToEndTest.java

@@ -0,0 +1,69 @@
+package com.example.app.time;
+
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import com.example.app.project.ProjectRepository;
+import com.example.app.user.UserRepository;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.util.Map;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class TimeEntryEndToEndTest {
+
+  @Autowired MockMvc mockMvc;
+  @Autowired ObjectMapper objectMapper;
+  @Autowired TimeEntryRepository timeEntryRepository;
+  @Autowired UserRepository userRepository;
+  @Autowired ProjectRepository projectRepository;
+
+  @AfterEach
+  void cleanup() {
+    timeEntryRepository.deleteAll();
+  }
+
+  @Test
+  void postTimeEntry_thenAppearInWeeklyReport() throws Exception {
+    long userId = userRepository.findAll().get(0).getId();
+    long projectId = projectRepository.findAll().get(0).getId();
+    LocalDate today = LocalDate.now();
+    String isoWeek = today.format(DateTimeFormatter.ofPattern("YYYY-'W'ww"));
+
+    String body =
+        objectMapper.writeValueAsString(
+            Map.of(
+                "userId",
+                userId,
+                "projectId",
+                projectId,
+                "entryDate",
+                today.toString(),
+                "durationMinutes",
+                90));
+
+    mockMvc
+        .perform(post("/api/time-entries").contentType(MediaType.APPLICATION_JSON).content(body))
+        .andExpect(status().isCreated())
+        .andExpect(jsonPath("$.durationMinutes").value(90));
+
+    mockMvc
+        .perform(
+            get("/api/reports/weekly")
+                .param("userId", String.valueOf(userId))
+                .param("week", isoWeek))
+        .andExpect(status().isOk())
+        .andExpect(jsonPath("$.weekTotalMinutes").value(90));
+  }
+}

backend/src/test/java/com/example/app/time/TimeEntryRepositoryTest.java

@@ -0,0 +1,56 @@
+package com.example.app.time;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.example.app.project.Project;
+import com.example.app.project.ProjectRepository;
+import com.example.app.user.User;
+import com.example.app.user.UserRepository;
+import java.time.LocalDate;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.test.context.TestPropertySource;
+
+@DataJpaTest
+@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
+@TestPropertySource(
+    properties = {"spring.jpa.hibernate.ddl-auto=validate", "spring.flyway.enabled=true"})
+class TimeEntryRepositoryTest {
+
+  @Autowired TimeEntryRepository timeEntryRepository;
+  @Autowired UserRepository userRepository;
+  @Autowired ProjectRepository projectRepository;
+
+  @Test
+  void findByUserAndDateRange_returnsOnlyEntriesInRange() {
+    User user = userRepository.findAll().get(0);
+    Project project = projectRepository.findAll().get(0);
+
+    LocalDate today = LocalDate.now();
+    TimeEntry inRange = entry(user, project, today, 60);
+    TimeEntry outOfRange = entry(user, project, today.minusDays(10), 30);
+    timeEntryRepository.saveAll(List.of(inRange, outOfRange));
+
+    List<TimeEntry> result =
+        timeEntryRepository.findByUserAndDateRange(
+            user.getId(), today.minusDays(1), today.plusDays(1));
+
+    assertThat(result).hasSize(1);
+    assertThat(result.get(0).getDurationMinutes()).isEqualTo(60);
+
+    // cleanup
+    timeEntryRepository.deleteAll(List.of(inRange, outOfRange));
+  }
+
+  private TimeEntry entry(User user, Project project, LocalDate date, int minutes) {
+    TimeEntry e = new TimeEntry();
+    e.setUser(user);
+    e.setProject(project);
+    e.setEntryDate(date);
+    e.setDurationMinutes(minutes);
+    return e;
+  }
+}