feat(eslint-config): set import/no-cycle to error (#206)

* feat(eslint-config): set import/no-cycle to error

* test(eslint-config): add import-happy & import-unhappy tests

packages/eslint-config/internal/import.js

@@ -29,6 +29,6 @@ module.exports = {
     ],
     'import/order': ['warn', { groups: [['builtin', 'external', 'internal']] }],
     'import/no-extraneous-dependencies': 'off', // need fine tuning
-    'import/no-cycle': 'off',
+    'import/no-cycle': 'error',
   },
 };

packages/eslint-config/test/import/__fixtures__/dep-a.js

@@ -0,0 +1 @@
+export function a() {}

packages/eslint-config/test/import/__fixtures__/dep-b.js

@@ -0,0 +1,3 @@
+import './import-unhappy.fixture';
+
+export function b() {}

packages/eslint-config/test/import/__fixtures__/import-happy.fixture.js

@@ -0,0 +1,3 @@
+import { a } from './dep-a';
+
+a();

packages/eslint-config/test/import/__fixtures__/import-unhappy.fixture.js

@@ -0,0 +1,3 @@
+import { b } from './dep-b';
+
+b();

packages/eslint-config/test/import/__snapshots__/import-happy.test.js.snap

@@ -0,0 +1,3 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`import / happy path happy 1`] = `""`;

packages/eslint-config/test/import/__snapshots__/import-unhappy.test.js.snap

@@ -0,0 +1,13 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`import / unhappy path unhappy 1`] = `
+"error: Dependency cycle detected (import/no-cycle) at packages/eslint-config/test/import/__fixtures__/import-unhappy.fixture.js:1:1:
+> 1 | import { b } from './dep-b';
+    | ^
+  2 | 
+  3 | b();
+  4 | 
+
+
+1 error found."
+`;

packages/eslint-config/test/import/import-happy.test.js

@@ -0,0 +1,27 @@
+import ESlint from 'eslint';
+import path from 'path';
+
+describe('import / happy path', () => {
+  const cli = new ESlint.CLIEngine({
+    cwd: path.join(__dirname, '..'),
+    useEslintrc: false,
+    baseConfig: {
+      extends: ['../internal/import'],
+      parserOptions: {
+        sourceType: 'module',
+      },
+      env: {
+        es6: true,
+      },
+    },
+  });
+
+  it('happy', () => {
+    const codeframe = cli.getFormatter('codeframe');
+    const report = cli.executeOnFiles([
+      path.join(__dirname, './__fixtures__/import-happy.fixture.js'),
+    ]);
+
+    expect(codeframe(report.results)).toMatchSnapshot();
+  });
+});

packages/eslint-config/test/import/import-unhappy.test.js

@@ -0,0 +1,27 @@
+import ESlint from 'eslint';
+import path from 'path';
+
+describe('import / unhappy path', () => {
+  const cli = new ESlint.CLIEngine({
+    cwd: path.join(__dirname, '..'),
+    useEslintrc: false,
+    baseConfig: {
+      extends: ['../internal/import'],
+      parserOptions: {
+        sourceType: 'module',
+      },
+      env: {
+        es6: true,
+      },
+    },
+  });
+
+  it('unhappy', () => {
+    const codeframe = cli.getFormatter('codeframe');
+    const report = cli.executeOnFiles([
+      path.join(__dirname, './__fixtures__/import-unhappy.fixture.js'),
+    ]);
+
+    expect(codeframe(report.results)).toMatchSnapshot();
+  });
+});