jest/valid-expect Correctness

✅ This rule is turned on by default.

What it does

Checks that expect() is called correctly.

Why is this bad?

expect() is a function that is used to assert values in tests. It should be called with a single argument, which is the value to be tested. If you call expect() with no arguments, or with more than one argument, it will not work as expected.

Example

Examples of incorrect code for this rule:

expect();
expect("something");
expect(true).toBeDefined;
expect(Promise.resolve("Hi!")).resolves.toBe("Hi!");

Examples of correct code for this rule:

expect("something").toEqual("something");
expect(true).toBeDefined();
expect(Promise.resolve("Hi!")).resolves.toBe("Hi!");

This rule is compatible with eslint-plugin-vitest, to use it, add the following configuration to your .eslintrc.json:

{
  "rules": {
    "vitest/valid-expect": "error"
  }
}

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny jest/valid-expect --jest-plugin

Config (.oxlintrc.json)

{
  "plugins": ["jest"],
  "rules": {
    "jest/valid-expect": "error"
  }
}

References

• Rule Source