Missing function coverage reporting in class without explicit constructor

[simon-kepplinger]

What version of Bun is running?

1.0.11

What platform is your computer?

Linux 6.5.6-76060506-generic x86_64 x86_64

What steps can reproduce the bug?

index.ts

export class Test {
  public test(): boolean {
    return true;
  }
}

index.test.ts

import { describe, expect, it } from 'bun:test';
import { Test } from './index.ts';

describe('Test', () => {
  it('should test', () => {
    const actual = new Test().test();
    expect(actual).toBe(true);
  });
});

What is the expected behavior?

I would expect 100% function coverage when running bun test --coverage

-----------|---------|---------|-------------------
File       | % Funcs | % Lines | Uncovered Line #s
-----------|---------|---------|-------------------
All files  |  100.00 |  100.00 |
 index.ts  |  100.00 |  100.00 | 
-----------|---------|---------|-------------------

What do you see instead?

bun test --coverage reports only 50% function coverage

bun test v1.0.11 (f7f6233e)

index.test.ts:
✓ Test > should test [0.07ms]
-----------|---------|---------|-------------------
File       | % Funcs | % Lines | Uncovered Line #s
-----------|---------|---------|-------------------
All files  |   50.00 |  100.00 |
 index.ts  |   50.00 |  100.00 | 
-----------|---------|---------|-------------------

 1 pass
 0 fail
 1 expect() calls
Ran 1 tests across 1 files. [12.00ms]

Additional information

Upon adding an empty constructor to the class, the reported function coverage increased to 100%. This occurred without any modifications to the test case.

export class Test {
  public constructor() {
  }
  
  public test(): boolean {
    return true;
  }
}

bun test --coverage prints

bun test v1.0.11 (f7f6233e)

index.test.ts:
✓ Test > should test [0.06ms]
-----------|---------|---------|-------------------
File       | % Funcs | % Lines | Uncovered Line #s
-----------|---------|---------|-------------------
All files  |  100.00 |  100.00 |
 index.ts  |  100.00 |  100.00 | 
-----------|---------|---------|-------------------

 1 pass
 0 fail
 1 expect() calls
Ran 1 tests across 1 files. [13.00ms]