ShouldBeZero matcher

[LeoColman]

Int, Double, Long, (...) should have a special matcher to verify if it's zero.

This matcher should also have an opposite, to verify it's not zero.

myInt.shouldBeZero()
myDouble.shouldNotBeZero()

Special cases to pay attention to: Double.NaN and Double.POSITIVE_INFINITY/Double.NEGATIVE_INFINITY.

These can be added to the kotlintest-assertions module. There can be a matcher for each numeric type, or a Number matcher that match them all.

An example on how to start the isZero method:

fun Number.isZero(): Boolean {
  return when(this) {
    is Double -> this == 0.0    // Verification for NaN
    is Float -> this == 0.0     // Verification for NaN
    else -> this.toLong() == 0L
  }
}

[sksamuel]

This could go in either 3.4 or 3.5 depending on time.