no-long-arrays-in-test-each.md

Disallow using long arrays with objects inside test.each() or it.each(). Force moving them out of the file (proper-tests/no-long-arrays-in-test-each)

💼 This rule is enabled in the ✅ recommended config.

Options

Name	Type
limit	Integer

Rule details

This rule disallows the usage of long arrays in test.each() calls.

The following code is considered errors:

test.each([
  {
    description: 'test case name #1',
    inputValue: 'a',
    expectedOutput: 'aa',
  },
  {
    description: 'test case name #2',
    inputValue: 'b',
    expectedOutput: 'bb',
  },
  {
    description: 'test case name #3',
    inputValue: 'c',
    expectedOutput: 'cc',
  },
  {
    description: 'test case name #4',
    inputValue: 'd',
    expectedOutput: 'dd',
  },
  {
    description: 'test case name #5',
    inputValue: 'e',
    expectedOutput: 'ee',
  },
  {
    description: 'test case name #6',
    inputValue: 'f',
    expectedOutput: 'ff',
  },
])('$description', ({ clientCountry, expectedPaymentMethod, processorName }) => {
  // ...
});

Consider extracting such long arrays to a separate files with for example .data.ts postfix.

The following code is considered correct:

// some-service.data.ts
export type TestCase = Readonly<{
  description: string;
  inputValue: string;
  expectedOutput: string;
}>;

export const testCases: TestCase[] = [
  {
    description: 'test case name #1',
    inputValue: 'a',
    expectedOutput: 'aa',
  },
  {
    description: 'test case name #2',
    inputValue: 'b',
    expectedOutput: 'bb',
  },
  {
    description: 'test case name #3',
    inputValue: 'c',
    expectedOutput: 'cc',
  },
  {
    description: 'test case name #4',
    inputValue: 'd',
    expectedOutput: 'dd',
  },
  {
    description: 'test case name #5',
    inputValue: 'e',
    expectedOutput: 'ee',
  },
  {
    description: 'test case name #6',
    inputValue: 'f',
    expectedOutput: 'ff',
  },
];

and now test is more readable:

test.each(testCases)('$description', ({ inputValue, expectedOutput }: TestCase) => {
  // ...
});