import {describe, expect, it} from 'bun:test';
import assertUnreachable from '../../../src/lang/assertUnreachable';

describe('assertUnreachable', () => {
  describe('when called with an unexpected value', () => {
    it('should throw an error containing the value', () => {
      const unreachableValue = 'unexpected' as never;

      expect(() => assertUnreachable(unreachableValue)).toThrow('Unreachable code: unexpected');
    });

    it('should handle numeric values in the error message', () => {
      const numericValue = 42 as never;

      expect(() => assertUnreachable(numericValue)).toThrow('Unreachable code: 42');
    });

    it('should always throw and never return', () => {
      const value = 'test' as never;
      let didThrow = false;

      try {
        assertUnreachable(value);
      } catch {
        didThrow = true;
      }

      expect(didThrow).toBe(true);
    });
  });
});