diff --git a/crates/oxc_linter/src/rules.rs b/crates/oxc_linter/src/rules.rs index cae305115..396e9aa59 100644 --- a/crates/oxc_linter/src/rules.rs +++ b/crates/oxc_linter/src/rules.rs @@ -153,6 +153,7 @@ mod jest { pub mod no_test_return_statement; pub mod prefer_called_with; pub mod prefer_equality_matcher; + pub mod prefer_expect_resolves; pub mod prefer_spy_on; pub mod prefer_strict_equal; pub mod prefer_to_be; @@ -458,6 +459,7 @@ oxc_macros::declare_all_lint_rules! { jest::no_test_return_statement, jest::prefer_called_with, jest::prefer_equality_matcher, + jest::prefer_expect_resolves, jest::prefer_spy_on, jest::prefer_strict_equal, jest::prefer_to_be, diff --git a/crates/oxc_linter/src/rules/jest/prefer_expect_resolves.rs b/crates/oxc_linter/src/rules/jest/prefer_expect_resolves.rs new file mode 100644 index 000000000..483f43da2 --- /dev/null +++ b/crates/oxc_linter/src/rules/jest/prefer_expect_resolves.rs @@ -0,0 +1,270 @@ +use oxc_ast::{ + ast::{Argument, CallExpression, Expression}, + AstKind, +}; +use oxc_diagnostics::{ + miette::{self, Diagnostic}, + thiserror::Error, +}; +use oxc_macros::declare_oxc_lint; +use oxc_span::Span; + +use crate::{ + context::LintContext, + fixer::Fix, + rule::Rule, + utils::{ + collect_possible_jest_call_node, parse_expect_jest_fn_call, ParsedExpectFnCall, + PossibleJestNode, + }, +}; + +#[derive(Debug, Error, Diagnostic)] +#[error("eslint-plugin-jest(prefer-expect-resolves): Prefer `await expect(...).resolves` over `expect(await ...)` syntax.")] +#[diagnostic(severity(warning), help("Use `await expect(...).resolves` instead"))] +struct ExpectResolves(#[label] pub Span); + +#[derive(Debug, Default, Clone)] +pub struct PreferExpectResolves; + +declare_oxc_lint!( + /// ### What it does + /// + /// When working with promises, there are two primary ways you can test the resolved + /// value: + /// 1. use the `resolve` modifier on `expect` + /// (`await expect(...).resolves.` style) + /// 2. `await` the promise and assert against its result + /// (`expect(await ...).` style) + /// + /// While the second style is arguably less dependent on `jest`, if the promise + /// rejects it will be treated as a general error, resulting in less predictable + /// behaviour and output from `jest`. + /// + /// Additionally, favoring the first style ensures consistency with its `rejects` + /// counterpart, as there is no way of "awaiting" a rejection. + /// + /// ### Example + /// + /// ```javascript + /// // valid + /// it('passes', async () => { + /// await expect(someValue()).resolves.toBe(true); + /// }); + /// it('is true', async () => { + /// const myPromise = Promise.resolve(true); + /// + /// await expect(myPromise).resolves.toBe(true); + /// }); + /// + /// it('errors', async () => { + /// await expect(Promise.reject(new Error('oh noes!'))).rejects.toThrowError( + /// 'oh noes!', + /// ); + /// }); + /// + /// // invalid + /// it('passes', async () => { + /// expect(await someValue()).toBe(true); + /// }); + /// it('is true', async () => { + /// const myPromise = Promise.resolve(true); + /// expect(await myPromise).toBe(true); + /// }); + /// ``` + PreferExpectResolves, + style, +); + +impl Rule for PreferExpectResolves { + fn run_once(&self, ctx: &LintContext) { + for possible_jest_node in &collect_possible_jest_call_node(ctx) { + Self::run(possible_jest_node, ctx); + } + } +} + +impl PreferExpectResolves { + fn run<'a>(possible_jest_node: &PossibleJestNode<'a, '_>, ctx: &LintContext<'a>) { + let node = possible_jest_node.node; + let AstKind::CallExpression(call_expr) = node.kind() else { + return; + }; + let Some(jest_expect_fn_call) = + parse_expect_jest_fn_call(call_expr, possible_jest_node, ctx) + else { + return; + }; + let Some(Expression::CallExpression(call_expr)) = jest_expect_fn_call.head.parent else { + return; + }; + let Some(argument) = call_expr.arguments.first() else { + return; + }; + let Argument::Expression(Expression::AwaitExpression(await_expr)) = argument else { + return; + }; + let Some(ident) = call_expr.callee.get_identifier_reference() else { + return; + }; + + ctx.diagnostic_with_fix(ExpectResolves(await_expr.span), || { + let content = Self::build_code(&jest_expect_fn_call, call_expr, ident.span, ctx); + Fix::new(content, call_expr.span) + }); + } + + fn build_code<'a>( + jest_expect_fn_call: &ParsedExpectFnCall, + call_expr: &CallExpression<'a>, + ident_span: Span, + ctx: &LintContext<'a>, + ) -> String { + let mut formatter = ctx.codegen(); + let first = call_expr.arguments.first().unwrap(); + let Argument::Expression(Expression::AwaitExpression(await_expr)) = first else { + return formatter.into_source_text(); + }; + + let offset = match &await_expr.argument { + Expression::CallExpression(call_expr) => call_expr.span.start - ident_span.end, + Expression::Identifier(promise_ident) => promise_ident.span.start - ident_span.end, + _ => 0, + }; + + let arg_span = Span::new( + call_expr.span.start + (ident_span.end - ident_span.start) + offset, + call_expr.span.end, + ); + + formatter.print_str(b"await"); + formatter.print_hard_space(); + formatter.print_str(jest_expect_fn_call.local.as_bytes()); + formatter.print(b'('); + formatter.print_str(arg_span.source_text(ctx.source_text()).as_bytes()); + formatter.print_str(b".resolves"); + formatter.into_source_text() + } +} + +#[test] +fn tests() { + use crate::tester::Tester; + + let pass = vec![ + ("expect.hasAssertions()", None), + ( + " + it('passes', async () => { + await expect(someValue()).resolves.toBe(true); + }); + ", + None, + ), + ( + " + it('is true', async () => { + const myPromise = Promise.resolve(true); + await expect(myPromise).resolves.toBe(true); + }); + ", + None, + ), + ( + " + it('errors', async () => { + await expect(Promise.reject(new Error('oh noes!'))).rejects.toThrowError( + 'oh noes!', + ); + }); + ", + None, + ), + ]; + + let fail = vec![ + ( + " + it('passes', async () => { + expect(await someValue(),).toBe(true); + }); + ", + None, + ), + ( + " + it('is true', async () => { + const myPromise = Promise.resolve(true); + expect(await myPromise).toBe(true); + }); + ", + None, + ), + ( + " + import { expect as pleaseExpect } from '@jest/globals'; + + it('is true', async () => { + const myPromise = Promise.resolve(true); + pleaseExpect(await myPromise).toBe(true); + }); + ", + None, + ), + ]; + + let fix = vec![ + ( + " + it('passes', async () => { + expect(await someValue(),).toBe(true); + }); + ", + " + it('passes', async () => { + await expect(someValue(),).resolves.toBe(true); + }); + ", + None, + ), + ( + " + it('is true', async () => { + const myPromise = Promise.resolve(true); + expect(await myPromise).toBe(true); + }); + ", + " + it('is true', async () => { + const myPromise = Promise.resolve(true); + await expect(myPromise).resolves.toBe(true); + }); + ", + None, + ), + ( + " + import { expect as pleaseExpect } from '@jest/globals'; + + it('is true', async () => { + const myPromise = Promise.resolve(true); + pleaseExpect(await myPromise).toBe(true); + }); + ", + " + import { expect as pleaseExpect } from '@jest/globals'; + + it('is true', async () => { + const myPromise = Promise.resolve(true); + await pleaseExpect(myPromise).resolves.toBe(true); + }); + ", + None, + ), + ]; + + Tester::new(PreferExpectResolves::NAME, pass, fail) + .with_jest_plugin(true) + .expect_fix(fix) + .test_and_snapshot(); +} diff --git a/crates/oxc_linter/src/snapshots/prefer_expect_resolves.snap b/crates/oxc_linter/src/snapshots/prefer_expect_resolves.snap new file mode 100644 index 000000000..e3c0126f2 --- /dev/null +++ b/crates/oxc_linter/src/snapshots/prefer_expect_resolves.snap @@ -0,0 +1,31 @@ +--- +source: crates/oxc_linter/src/tester.rs +assertion_line: 151 +expression: prefer_expect_resolves +--- + ⚠ eslint-plugin-jest(prefer-expect-resolves): Prefer `await expect(...).resolves` over `expect(await ...)` syntax. + ╭─[prefer_expect_resolves.tsx:3:28] + 2 │ it('passes', async () => { + 3 │ expect(await someValue(),).toBe(true); + · ───────────────── + 4 │ }); + ╰──── + help: Use `await expect(...).resolves` instead + + ⚠ eslint-plugin-jest(prefer-expect-resolves): Prefer `await expect(...).resolves` over `expect(await ...)` syntax. + ╭─[prefer_expect_resolves.tsx:4:28] + 3 │ const myPromise = Promise.resolve(true); + 4 │ expect(await myPromise).toBe(true); + · ─────────────── + 5 │ }); + ╰──── + help: Use `await expect(...).resolves` instead + + ⚠ eslint-plugin-jest(prefer-expect-resolves): Prefer `await expect(...).resolves` over `expect(await ...)` syntax. + ╭─[prefer_expect_resolves.tsx:6:34] + 5 │ const myPromise = Promise.resolve(true); + 6 │ pleaseExpect(await myPromise).toBe(true); + · ─────────────── + 7 │ }); + ╰──── + help: Use `await expect(...).resolves` instead