Add file utility functions with unit tests (#48)

- Introduced `fileUtils.ts` containing `readJsonFile` and
`writeJsonFile` functions for reading and writing JSON files,
respectively.
- Implemented error handling using `FileUtilsError` for invalid paths
and file operation failures.
- Created `fileUtils.test.ts` to validate the functionality of the file
utility functions, ensuring proper error handling and file operations.

These additions enhance file management capabilities and improve test
coverage for file-related operations.

Author: anatolyshipitz

workers/main/src/activities/fetchFinancialData.ts

@@ -0,0 +1 @@
+export * from './weeklyFinancialReports';

workers/main/src/activities/index.ts

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+import { afterEach, beforeEach, describe, expect, it, Mock, vi } from 'vitest';
+
+import { AppError } from '../../common/errors';
+import { writeJsonFile } from '../../common/fileUtils';
+import { RedminePool } from '../../common/RedminePool';
+import { getTargetUnits } from './getTargetUnits';
+
+type TargetUnit = {
+  group_id: number;
+  group_name: string;
+  project_id: number;
+  project_name: string;
+  user_id: number;
+  username: string;
+  spent_on: string;
+  total_hours: number;
+};
+
+interface TargetUnitRepositoryMock {
+  mockClear: () => void;
+  mockImplementation: (
+    impl: () => { getTargetUnits: () => Promise<TargetUnit[]> },
+  ) => void;
+}
+
+interface RedminePoolMock {
+  mockClear: () => void;
+  mockImplementation: (
+    impl: () => { getPool: () => string; endPool: () => void },
+  ) => void;
+}
+
+const defaultUnit: TargetUnit = {
+  group_id: 1,
+  group_name: 'Group',
+  project_id: 2,
+  project_name: 'Project',
+  user_id: 3,
+  username: 'User',
+  spent_on: '2024-06-01',
+  total_hours: 8,
+};
+
+function createMockUnit(overrides: Partial<TargetUnit> = {}): TargetUnit {
+  return { ...defaultUnit, ...overrides };
+}
+
+async function setupTargetUnitRepositoryMock(): Promise<TargetUnitRepositoryMock> {
+  const imported = await vi.importMock(
+    '../../services/TargetUnit/TargetUnitRepository',
+  );
+  const repo = vi.mocked(
+    imported.TargetUnitRepository,
+  ) as TargetUnitRepositoryMock;
+
+  repo.mockClear();
+
+  return repo;
+}
+
+function setupRedminePoolMock(endPool: Mock) {
+  (RedminePool as unknown as RedminePoolMock).mockClear();
+  (RedminePool as unknown as RedminePoolMock).mockImplementation(() => ({
+    getPool: vi.fn(() => 'mockPool'),
+    endPool,
+  }));
+}
+
+vi.mock('../../common/RedminePool', () => ({
+  RedminePool: vi.fn().mockImplementation(() => ({
+    getPool: vi.fn(() => 'mockPool'),
+    endPool: vi.fn(),
+  })),
+}));
+vi.mock('../../services/TargetUnit/TargetUnitRepository', () => ({
+  TargetUnitRepository: vi.fn(),
+}));
+vi.mock('../../common/fileUtils', () => ({
+  writeJsonFile: vi.fn(),
+}));
+vi.mock('../../configs/redmineDatabase', () => ({
+  redmineDatabaseConfig: {},
+}));
+
+describe('getTargetUnits', () => {
+  const mockUnits: TargetUnit[] = [createMockUnit()];
+  const mockFile =
+    'data/weeklyFinancialReportsWorkflow/getTargetUnits/target-units-123.json';
+  let writeJsonFileMock: Mock;
+  let TargetUnitRepository: TargetUnitRepositoryMock;
+  let endPool: Mock;
+  let dateSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(async () => {
+    dateSpy = vi.spyOn(Date, 'now').mockReturnValue(123);
+    writeJsonFileMock = vi.mocked(writeJsonFile);
+    writeJsonFileMock.mockClear();
+    TargetUnitRepository = await setupTargetUnitRepositoryMock();
+    endPool = vi.fn();
+    setupRedminePoolMock(endPool);
+  });
+
+  afterEach(() => {
+    dateSpy.mockRestore();
+  });
+
+  const mockRepo = (success = true) => {
+    TargetUnitRepository.mockImplementation(() => ({
+      getTargetUnits: success
+        ? vi.fn().mockResolvedValue(mockUnits)
+        : vi.fn().mockRejectedValue(new Error('fail-get')),
+    }));
+  };
+
+  it('returns fileLink when successful', async () => {
+    mockRepo(true);
+    writeJsonFileMock.mockResolvedValue(undefined);
+    const result = await getTargetUnits();
+
+    expect(result).toEqual({ fileLink: mockFile });
+    expect(writeJsonFile).toHaveBeenCalledWith(mockFile, mockUnits);
+  });
+
+  it('throws AppError when repo.getTargetUnits throws', async () => {
+    mockRepo(false);
+    writeJsonFileMock.mockResolvedValue(undefined);
+    await expect(getTargetUnits()).rejects.toThrow(AppError);
+    await expect(getTargetUnits()).rejects.toThrow(
+      'Failed to get Target Units',
+    );
+  });
+
+  it('throws AppError when writeJsonFile throws', async () => {
+    mockRepo(true);
+    writeJsonFileMock.mockRejectedValue(new Error('fail-write'));
+    await expect(getTargetUnits()).rejects.toThrow(AppError);
+    await expect(getTargetUnits()).rejects.toThrow(
+      'Failed to get Target Units',
+    );
+  });
+
+  it('always ends the Redmine pool', async () => {
+    mockRepo(true);
+    writeJsonFileMock.mockResolvedValue(undefined);
+    await getTargetUnits();
+    expect(endPool).toHaveBeenCalled();
+  });
+});

workers/main/src/activities/weeklyFinancialReports/getTargetUnits.test.ts

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+import { AppError } from '../../common/errors';
+import { writeJsonFile } from '../../common/fileUtils';
+import { RedminePool } from '../../common/RedminePool';
+import { redmineDatabaseConfig } from '../../configs/redmineDatabase';
+import { TargetUnitRepository } from '../../services/TargetUnit/TargetUnitRepository';
+
+interface GetTargetUnitsResult {
+  fileLink: string;
+}
+
+export const getTargetUnits = async (): Promise<GetTargetUnitsResult> => {
+  const redminePool = new RedminePool(redmineDatabaseConfig);
+
+  try {
+    const pool = redminePool.getPool();
+
+    const repo = new TargetUnitRepository(pool);
+    const result = await repo.getTargetUnits();
+    const filename = `data/weeklyFinancialReportsWorkflow/getTargetUnits/target-units-${Date.now()}.json`;
+
+    await writeJsonFile(filename, result);
+
+    return { fileLink: filename };
+  } catch (err) {
+    const message = err instanceof Error ? err.message : String(err);
+
+    throw new AppError('Failed to get Target Units', message);
+  } finally {
+    await redminePool.endPool();
+  }
+};

workers/main/src/activities/weeklyFinancialReports/getTargetUnits.ts

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+export * from './getTargetUnits';

workers/main/src/activities/weeklyFinancialReports/index.ts

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+vi.mock('fs', () => ({
+  promises: {
+    readFile: vi.fn(),
+    writeFile: vi.fn(),
+    mkdir: vi.fn(),
+  },
+}));
+
+import { promises as fs } from 'fs';
+import path from 'path';
+import { afterEach, beforeEach, describe, expect, test, vi } from 'vitest';
+
+import { FileUtilsError } from './errors';
+import { readJsonFile, writeJsonFile } from './fileUtils';
+
+describe('fileUtils', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  describe('readJsonFile', () => {
+    test('reads and parses JSON file', async () => {
+      vi.mocked(fs.readFile).mockResolvedValueOnce('{"a":1}');
+      const result = await readJsonFile<{ a: number }>('test.json');
+
+      expect(result).toEqual({ a: 1 });
+      expect(fs.readFile).toHaveBeenCalledWith('test.json', 'utf-8');
+    });
+
+    test('throws FileUtilsError for invalid JSON', async () => {
+      vi.mocked(fs.readFile).mockResolvedValueOnce('not-json');
+      await expect(readJsonFile('bad.json')).rejects.toBeInstanceOf(
+        FileUtilsError,
+      );
+    });
+
+    test('throws FileUtilsError if fs.readFile throws', async () => {
+      vi.mocked(fs.readFile).mockRejectedValueOnce(new Error('fail'));
+      await expect(readJsonFile('fail.json')).rejects.toBeInstanceOf(
+        FileUtilsError,
+      );
+    });
+  });
+
+  describe('writeJsonFile', () => {
+    test('writes JSON file and creates directory', async () => {
+      vi.mocked(fs.mkdir).mockResolvedValueOnce(undefined);
+      vi.mocked(fs.writeFile).mockResolvedValueOnce(undefined);
+      const filePath = 'dir/file.json';
+      const data = { b: 2 };
+
+      await writeJsonFile(filePath, data);
+      expect(fs.mkdir).toHaveBeenCalledWith(path.dirname(filePath), {
+        recursive: true,
+      });
+      expect(fs.writeFile).toHaveBeenCalledWith(
+        filePath,
+        JSON.stringify(data, null, 2),
+        'utf-8',
+      );
+    });
+
+    test('throws FileUtilsError if fs.mkdir throws', async () => {
+      vi.mocked(fs.mkdir).mockRejectedValueOnce(new Error('fail'));
+      await expect(writeJsonFile('fail.json', {})).rejects.toBeInstanceOf(
+        FileUtilsError,
+      );
+    });
+
+    test('throws FileUtilsError if fs.writeFile throws', async () => {
+      vi.mocked(fs.mkdir).mockResolvedValueOnce(undefined);
+      vi.mocked(fs.writeFile).mockRejectedValueOnce(new Error('fail'));
+      await expect(writeJsonFile('fail2.json', {})).rejects.toBeInstanceOf(
+        FileUtilsError,
+      );
+    });
+  });
+});

workers/main/src/common/fileUtils.test.ts

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+import { promises as fs } from 'fs';
+import path from 'path';
+
+import { FileUtilsError } from './errors';
+
+export async function readJsonFile<T = object>(filePath: string): Promise<T> {
+  try {
+    const content = await fs.readFile(filePath, 'utf-8');
+    const parsed = JSON.parse(content) as T;
+
+    return parsed;
+  } catch {
+    throw new FileUtilsError(
+      `Failed to read or parse JSON file at "${filePath}"`,
+    );
+  }
+}
+
+export async function writeJsonFile<T = object>(
+  filePath: string,
+  data: T,
+): Promise<void> {
+  try {
+    const content = JSON.stringify(data, null, 2);
+    const dir = path.dirname(filePath);
+
+    await fs.mkdir(dir, { recursive: true });
+    await fs.writeFile(filePath, content, 'utf-8');
+  } catch {
+    throw new FileUtilsError(`Failed to write JSON file at "${filePath}"`);
+  }
+}