Grow output buffer when needed when reporting test outcomes (JS/Native)

[kubukoz]

Closes #724.

[kubukoz]

thought: two words about this:

• 2048 is now the initial length of the array, but BAOS makes it grow when needed
• I tried to switch to StringBuilder as suggested, but in order to keep the reader working, the output should have constant-length encoding of numbers, and it seemed bothersome to try and pad them to make it work. Instead, DataOutputStream encodes the numbers in binary as expected.
• I'm not super comfortable with this encoding even in its current shape, because it assumes the bytes can be safely decoded from UTF-8 (new String) and encoded again (.getBytes()) without data loss, and I don't think that's generally true.

For example, this prints false:

val bb = ByteBuffer.allocate(20)
bb.putInt(42)
bb.putDouble(21.37)
val result = bb.array()
println(new String(result).getBytes().toList == result.toList)

so... I think ultimately the right solution would indeed be to use StringBuilder, albeit with a different encoding.

Thoughts?

[kubukoz]

ah, miraculously our doubles never have the floating point part (.toMillis.toDouble). However, even 50 000 ms (50 seconds) is enough to fail the roundrip.

[kubukoz]

ok, added some tests - 206de20 - for the time being, encoding the bytes in base64 to bypass the UTF-8 problem, just to have a green build. Maybe it's fine.

[kubukoz]

finally, living proof of the roundtrip problem:

package demo

import cats.effect.IO
import weaver._
import concurrent.duration._

object DemoTest extends SimpleIOSuite {

  test("this should fail rather than hang") {
    IO.unit.as(failure("verbosity goes here"))
  }
}

object DemoTest2 extends SimpleIOSuite {

  test("this should fail rather than hang") {
    IO.unit.as(failure("verbosity goes here"))
  }
}

0.8.3:

another run:

206de20 :