ADD unit tests, split and refactor source code

__test__/common.spec.js

@@ -0,0 +1,123 @@
+const fs = require('fs');
+const childProcess = require('child_process');
+const common = require('../src/common');
+
+jest.mock('fs');
+jest.mock('child_process');
+jest.mock('mkdirp');
+
+describe('common', () => {
+  describe('getInstallationPath()', () => {
+    let callback, env;
+
+    beforeEach(() => {
+      callback = jest.fn();
+
+      env = { ...process.env };
+    });
+
+    afterEach(() => {
+      process.env = env;
+    });
+
+    it('should get binaries path from `npm bin`', () => {
+      childProcess.exec.mockImplementationOnce((_cmd, cb) => cb(null, '/usr/local/bin'));
+
+      common.getInstallationPath(callback);
+
+      expect(callback).toHaveBeenCalledWith(null, '/usr/local/bin');
+    });
+
+    it('should get binaries path from env', () => {
+      childProcess.exec.mockImplementationOnce((_cmd, cb) => cb(new Error()));
+
+      process.env.npm_config_prefix = '/usr/local';
+
+      common.getInstallationPath(callback);
+
+      expect(callback).toHaveBeenCalledWith(null, '/usr/local/bin');
+    });
+
+    it('should call callback with error if binaries path is not found', () => {
+      childProcess.exec.mockImplementationOnce((_cmd, cb) => cb(new Error()));
+
+      process.env.npm_config_prefix = undefined;
+
+      common.getInstallationPath(callback);
+
+      expect(callback).toHaveBeenCalledWith(new Error('Error finding binary installation directory'));
+    });
+  });
+
+  describe('parsePackageJson()', () => {
+    let _process;
+
+    beforeEach(() => {
+      _process = { ...global.process };
+    });
+
+    afterEach(() => {
+      global.process = _process;
+    });
+
+    describe('validation', () => {
+      it('should return if architecture is unsupported', () => {
+        process.arch = 'mips';
+
+        expect(common.parsePackageJson()).toBeUndefined();
+      });
+
+      it('should return if platform is unsupported', () => {
+        process.platform = 'amiga';
+
+        expect(common.parsePackageJson()).toBeUndefined();
+      });
+
+      it('should return if package.json does not exist', () => {
+        fs.existsSync.mockReturnValueOnce(false);
+
+        expect(common.parsePackageJson()).toBeUndefined();
+      });
+    });
+
+    describe('variable replacement', () => {
+      it('should append .exe extension on windows platform', () => {
+        fs.existsSync.mockReturnValueOnce(true);
+        fs.readFileSync.mockReturnValueOnce(JSON.stringify({
+          version: '1.0.0',
+          goBinary: {
+            name: 'command',
+            path: './bin',
+            url: 'https://github.com/foo/bar/releases/v{{version}}/assets/command{{win_ext}}'
+          }
+        }));
+
+        process.platform = 'win32';
+
+        expect(common.parsePackageJson()).toMatchObject({
+          binName: 'command.exe',
+          url: 'https://github.com/foo/bar/releases/v1.0.0/assets/command.exe'
+        });
+      });
+
+      it('should not append .exe extension on platform different than windows', () => {
+        fs.existsSync.mockReturnValueOnce(true);
+        fs.readFileSync.mockReturnValueOnce(JSON.stringify({
+          version: '1.0.0',
+          goBinary: {
+            name: 'command',
+            path: './bin',
+            url: 'https://github.com/foo/bar/releases/v{{version}}/assets/command{{win_ext}}'
+          }
+        }));
+
+        process.platform = 'darwin';
+
+        expect(common.parsePackageJson()).toMatchObject({
+          binName: 'command',
+          url: 'https://github.com/foo/bar/releases/v1.0.0/assets/command'
+        });
+      });
+    });
+  });
+});