feat(no-conditional-in-test): ban optional chaining (#1933)

Author: christopher-buss

docs/rules/no-conditional-in-test.md

@@ -12,7 +12,7 @@ devoted to it.
 ## Rule details
 
 This rule reports on any use of a conditional statement such as `if`, `switch`,
-and ternary expressions.
+ternary expressions, and optional chaining.
 
 Examples of **incorrect** code for this rule:
 
@@ -36,7 +36,11 @@ it('bar', () => {
   expect(fixtures.length).toBeGreaterThan(-1);
 });
 
-it('baz', async () => {
+it('baz', () => {
+  const value = obj?.bar;
+});
+
+it('qux', async () => {
   const promiseValue = () => {
     return something instanceof Promise
       ? something
@@ -77,7 +81,11 @@ const promiseValue = something => {
   return something instanceof Promise ? something : Promise.resolve(something);
 };
 
-it('baz', async () => {
+it('baz', () => {
+  const value = obj!.bar;
+});
+
+it('qux', async () => {
   await expect(promiseValue()).resolves.toBe(1);
 });
 ```

src/rules/__tests__/no-conditional-in-test.test.ts

@@ -5,7 +5,7 @@ import { FlatCompatRuleTester as RuleTester, espreeParser } from './test-utils';
 const ruleTester = new RuleTester({
   parser: espreeParser,
   parserOptions: {
-    ecmaVersion: 2015,
+    ecmaVersion: 2020,
   },
 });
 
@@ -949,3 +949,224 @@ ruleTester.run('if statements', rule, {
     },
   ],
 });
+
+ruleTester.run('optional chaining', rule, {
+  valid: [
+    'const x = obj?.foo',
+    dedent`
+      const foo = obj?.bar;
+
+      it('foo', () => {
+        expect(foo).toBe(undefined);
+      });
+    `,
+    dedent`
+      describe('foo', () => {
+        const val = obj?.bar;
+      })
+    `,
+    dedent`
+      describe('foo', () => {
+        beforeEach(() => {
+          const val = obj?.bar;
+        });
+      })
+    `,
+    dedent`
+      describe('foo', () => {
+        afterEach(() => {
+          const val = obj?.bar;
+        });
+      })
+    `,
+    dedent`
+      const values = something.map(thing => thing?.foo);
+
+      it('valid', () => {
+        expect(values).toStrictEqual(['foo']);
+      });
+    `,
+    dedent`
+      describe('valid', () => {
+        const values = something.map(thing => thing?.foo);
+        it('still valid', () => {
+          expect(values).toStrictEqual(['foo']);
+        });
+      });
+    `,
+  ],
+  invalid: [
+    {
+      code: dedent`
+        it('foo', () => {
+          const value = obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 17,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it('foo', () => {
+          obj?.foo?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it('foo', () => {
+          obj?.foo();
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it('foo', () => {
+          obj?.[key];
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it.skip('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it.only('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        test('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        xtest('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        fit('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        xit('foo', () => {
+          obj?.bar;
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 3,
+          line: 2,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        describe('foo', () => {
+          it('bar', () => {
+            obj?.bar;
+          })
+        })
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 5,
+          line: 3,
+        },
+      ],
+    },
+    {
+      code: dedent`
+        it('is invalid', () => {
+          const values = something.map(thing => thing?.foo);
+
+          expect(values).toStrictEqual(['foo']);
+        });
+      `,
+      errors: [
+        {
+          messageId: 'conditionalInTest',
+          column: 41,
+          line: 2,
+        },
+      ],
+    },
+  ],
+});

src/rules/no-conditional-in-test.ts

@@ -41,6 +41,7 @@ export default createRule({
       SwitchStatement: maybeReportConditional,
       ConditionalExpression: maybeReportConditional,
       LogicalExpression: maybeReportConditional,
+      ChainExpression: maybeReportConditional,
     };
   },
 });