Verbose API results

[smartclash]

This PR is dependent on #74

TSD either returns a null array if there is no test failures or an array of Diagnostic objects. This PR aims to make TSD return with ExtendedDiagnostic object no matter if the tests fail or not.

Merging this PR allows custom test runners like Jest to report the number of assertions it evaluated in each file.

It also means that it introduces a breaking change because TSD now returns...

• An object with numTests and null diagnostics array if all tests passed.

{
    numTests: 1024, // Total number of tests it ran through
    diagnostics: [] // No failed test cases
}

• An object with numTests and an diagnostics array populated with test fail reports if a test is failed.

{
    numTests: 1024, // Total number of tests it ran through
    diagnostics: [
        {
            fileName: 'add.test-d.ts',
            message: 'A message here',
            severity: 'error',
            line: 10,
            column: 34,
        },
        ...
    ]
}

---

• Unit tests have been added
• A more detailed explanation can be found here - Reporting Test Count

---

This PR is Co-Authored By:

• Karan Sanjeev xalphamanx@tuta.io
• SaurabhAgarwala saur.agarwala@gmail.com

[Ethan-Arrowood]

this looks really good! nice work!

[SimenB]

rebase this now that #74 has landed?

[SimenB]

Still very interested in seeing this land 😀

[tommy-mitchell]

Instead of making a breaking change, maybe tsd can just have verbose: boolean option?

const diagnostics = await tsd();
//=> Diagnostic[]

console.log(diagnostics.length);
//=> '0'

const verboseResults = await tsd({verbose: true});
//=> {testCount: number, diagnostics: Diagnostic[]}

console.log(verboseResults.testCount);
//=> '1024'

console.log(verboseResults.diagnostics.length);
//=> '0'

[sindresorhus]

I'm fine with this change. Having an object also gives us the opportunity to add additional properties in the future.

[sindresorhus]

Instead of making a breaking change, maybe tsd can just have verbose: boolean option?

I don't like options that change the return value type.

I think a breaking change is ok here. Programmatic use is not that common.