Add a test

lib/cli/src/automigrate/fixes/npm7.test.ts

@@ -0,0 +1,47 @@
+import { NPMProxy } from '../../js-package-manager/NPMProxy';
+import { npm7 } from './npm7';
+
+const mockExecuteCommand = jest.fn();
+class MockedNPMProxy extends NPMProxy {
+  executeCommand(...args) {
+    return mockExecuteCommand(...args);
+  }
+}
+
+function mockExecuteResults(map: Record<string, string>) {
+  mockExecuteCommand.mockImplementation((command, args) => {
+    const commandString = `${command} ${args.join(' ')}`;
+    if (map[commandString]) return map[commandString];
+
+    throw new Error(`Unexpected execution of '${commandString}'`);
+  });
+}
+
+describe('npm7 fix', () => {
+  describe('npm < 7', () => {
+    it('does not match', async () => {
+      mockExecuteResults({ 'npm --version': '6.0.0' });
+      expect(await npm7.check({ packageManager: new MockedNPMProxy() })).toEqual(null);
+    });
+  });
+
+  describe('npm 7+', () => {
+    it('matches if config is not installed', async () => {
+      mockExecuteResults({
+        'npm --version': '7.0.0',
+        'npm config get legacy-peer-deps --location=project': 'false',
+      });
+      expect(await npm7.check({ packageManager: new MockedNPMProxy() })).toEqual({
+        npmVersion: '7.0.0',
+      });
+    });
+
+    it('does not match if config is installed', async () => {
+      mockExecuteResults({
+        'npm --version': '7.0.0',
+        'npm config get legacy-peer-deps --location=project': 'true',
+      });
+      expect(await npm7.check({ packageManager: new MockedNPMProxy() })).toEqual(null);
+    });
+  });
+});