test(updaters): add unit tests for CustomUpdater

- Added tests for canHandle method
- Added tests for getCurrentVersion method
- Added tests for bumpVersion method
- Mocked dependencies using vitest
- Improved test coverage

Author: taj54

tests/updaters/customUpdater.test.ts

@@ -0,0 +1,90 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { CustomUpdater } from '../../src/updaters/customUpdater';
+import { FileHandler, ManifestParser } from '../../src/utils';
+import * as core from '@actions/core';
+
+vi.mock('../../src/utils/fileHandler');
+vi.mock('../../src/utils/manifestParser');
+vi.mock('@actions/core');
+
+describe('CustomUpdater', () => {
+  let customUpdater: CustomUpdater;
+  let mockFileHandler: vi.Mocked<FileHandler>;
+  let mockManifestParser: vi.Mocked<ManifestParser>;
+
+  const filePath = 'test.txt';
+  const variableName = 'APP_VERSION';
+
+  beforeEach(() => {
+    mockFileHandler = new FileHandler() as vi.Mocked<FileHandler>;
+    mockManifestParser = new ManifestParser(mockFileHandler) as vi.Mocked<ManifestParser>;
+    customUpdater = new CustomUpdater(filePath, variableName);
+
+    // Mock the constructor's internal assignments
+    (customUpdater as any).fileHandler = mockFileHandler;
+    (customUpdater as any).manifestParser = mockManifestParser;
+  });
+
+  it('should always return true for canHandle', () => {
+    expect(customUpdater.canHandle()).toBe(true);
+  });
+
+  describe('getCurrentVersion', () => {
+    it('should return the current version if found', () => {
+      mockManifestParser.getVersion.mockReturnValue('1.0.0');
+      expect(customUpdater.getCurrentVersion()).toBe('1.0.0');
+      expect(mockManifestParser.getVersion).toHaveBeenCalledWith(
+        filePath,
+        'regex',
+        expect.objectContaining({ regex: expect.any(RegExp) }),
+      );
+    });
+
+    it('should return null if version is not found', () => {
+      mockManifestParser.getVersion.mockReturnValue(null);
+      expect(customUpdater.getCurrentVersion()).toBeNull();
+    });
+
+    it('should return null and log debug message if manifestParser.getVersion throws an error', () => {
+      const error = new Error('Parse error');
+      mockManifestParser.getVersion.mockImplementation(() => {
+        throw error;
+      });
+      const coreDebugSpy = vi.spyOn(core, 'debug').mockImplementation(() => {});
+
+      expect(customUpdater.getCurrentVersion()).toBeNull();
+      expect(coreDebugSpy).toHaveBeenCalledWith(
+        `Could not read or parse version from ${filePath}: ${error}`,
+      );
+    });
+  });
+
+  describe('bumpVersion', () => {
+    it('should successfully bump the version', () => {
+      vi.spyOn(customUpdater, 'getCurrentVersion').mockReturnValue('1.0.0');
+      mockManifestParser.updateVersion.mockReturnValue(undefined);
+      const coreInfoSpy = vi.spyOn(core, 'info').mockImplementation(() => {});
+
+      const newVersion = customUpdater.bumpVersion('patch');
+
+      expect(newVersion).toBe('1.0.1');
+      expect(mockManifestParser.updateVersion).toHaveBeenCalledWith(
+        filePath,
+        '1.0.1',
+        'regex',
+        expect.objectContaining({ regexReplace: expect.any(RegExp) }),
+      );
+      expect(coreInfoSpy).toHaveBeenCalledWith(
+        `Bumped ${variableName} in ${filePath} from 1.0.0 to 1.0.1`,
+      );
+    });
+
+    it('should throw an error if current version is not found', () => {
+      vi.spyOn(customUpdater, 'getCurrentVersion').mockReturnValue(null);
+
+      expect(() => customUpdater.bumpVersion('patch')).toThrow(
+        `Could not find current version for variable '${variableName}' in file '${filePath}'`,
+      );
+    });
+  });
+});