eslint-plugin: add tests for no-undeclared-imports + fixes

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/eslint-plugin/src/__fixtures__/monorepo/packages/bar/package.json

@@ -3,7 +3,10 @@
   "backstage": {
     "role": "frontend-plugin"
   },
-  "peerDependencies": {
-    "react": "*"
+  "dependencies": {
+    "react-router": "*"
+  },
+  "devDependencies": {
+    "react-router-dom": "*"
   }
 }

packages/eslint-plugin/src/__fixtures__/monorepo/packages/foo/package.json

@@ -1,7 +1,12 @@
 {
   "name": "@internal/foo",
   "dependencies": {
-    "@internal/bar": "1.0.0",
+    "@internal/bar": "1.0.0"
+  },
+  "devDependencies": {
     "lodash": "*"
+  },
+  "peerDependencies": {
+    "react": "*"
   }
 }

packages/eslint-plugin/src/no-undeclared-imports.test.ts

@@ -0,0 +1,194 @@
+/*
+ * Copyright 2023 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { RuleTester } from 'eslint';
+import path from 'path';
+import rule from '../rules/no-undeclared-imports';
+
+const RULE = 'no-undeclared-imports';
+const FIXTURE = path.resolve(__dirname, '__fixtures__/monorepo');
+
+const ERR_UNDECLARED = (
+  name: string,
+  field: string,
+  path: string,
+  flag?: string,
+) => ({
+  message: `${name} must be declared in ${field} of ${path}/package.json, run 'yarn --cwd ${path} add${
+    flag ? ` ${flag}` : ''
+  } ${name}' from the project root.`,
+});
+const ERR_SWITCHED = (
+  name: string,
+  old: string,
+  field: string,
+  path: string,
+) => ({
+  message: `${name} is declared in ${old}, but should be moved to ${field} in ${path}/package.json.`,
+});
+
+process.chdir(FIXTURE);
+
+const ruleTester = new RuleTester({
+  parserOptions: {
+    sourceType: 'module',
+    ecmaVersion: 2021,
+  },
+});
+
+ruleTester.run(RULE, rule, {
+  valid: [
+    {
+      code: `import '@internal/foo'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.ts'),
+    },
+    {
+      code: `import '@internal/bar'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.ts'),
+    },
+    {
+      code: `import 'react'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.ts'),
+    },
+    {
+      code: `import '@internal/foo'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.test.ts'),
+    },
+    {
+      code: `import '@internal/bar'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.test.ts'),
+    },
+    {
+      code: `import 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.test.ts'),
+    },
+    {
+      code: `import 'react'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.test.ts'),
+    },
+    {
+      // We're only able to validate literals
+      code: `require('lod' + 'ash')`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+    },
+  ],
+  invalid: [
+    {
+      code: `import 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.ts'),
+      errors: [
+        ERR_SWITCHED(
+          'lodash',
+          'devDependencies',
+          'dependencies',
+          'packages/foo',
+        ),
+      ],
+    },
+    {
+      code: `import 'react-router'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [
+        ERR_SWITCHED(
+          'react-router',
+          'dependencies',
+          'peerDependencies',
+          'packages/bar',
+        ),
+      ],
+    },
+    {
+      code: `import 'react-router-dom'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [
+        ERR_SWITCHED(
+          'react-router-dom',
+          'devDependencies',
+          'peerDependencies',
+          'packages/bar',
+        ),
+      ],
+    },
+    {
+      code: `import 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import { debounce } from 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import * as _ from 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import _ from 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import('lodash')`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `require('lodash')`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [ERR_UNDECLARED('lodash', 'dependencies', 'packages/bar')],
+    },
+    {
+      code: `import 'lodash'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.test.ts'),
+      errors: [
+        ERR_UNDECLARED('lodash', 'devDependencies', 'packages/bar', '--dev'),
+      ],
+    },
+    {
+      code: `import 'react'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.ts'),
+      errors: [
+        ERR_UNDECLARED('react', 'peerDependencies', 'packages/bar', '--peer'),
+      ],
+    },
+    {
+      code: `import 'react'`,
+      filename: path.join(FIXTURE, 'packages/bar/src/index.test.ts'),
+      errors: [
+        ERR_UNDECLARED('react', 'peerDependencies', 'packages/bar', '--peer'),
+      ],
+    },
+    {
+      code: `import 'react-dom'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.ts'),
+      errors: [ERR_UNDECLARED('react-dom', 'dependencies', 'packages/foo')],
+    },
+    {
+      code: `import 'react-dom'`,
+      filename: path.join(FIXTURE, 'packages/foo/src/index.test.ts'),
+      errors: [
+        ERR_UNDECLARED('react-dom', 'devDependencies', 'packages/foo', '--dev'),
+      ],
+    },
+  ],
+});