provide VarArgFormatter

[jangalinski]

When using given().something_with_varargs_params_$("foo","bar") I want to have nice formatting of the vararg params, currently its something like "something with varargs params String@12345"

[janschaefer]

You can use the @Table annotation to format Arrays and varargs. See http://jgiven.org/userguide/#_tables_as_parameters

[zambrovski]

Sure, @Table is nice, but a table breaks the page flow of the test description. For short lists, a comma-separated list is adequate too.

[janschaefer]

Ok, I understand and I agree. But then this would be just an alternative implementation to format any lists, right? So maybe it should not only format varargs, but also any kind of Iterables. It should then also be named differently, IMHO.

[janschaefer]

What about @CommaSeparated? Maybe even with an attribute that defines the separator? @CommaSeparated( sep = ';');

[janschaefer]

I just tried to reproduce this issue and JGiven already formats varargs parameters as a comma-separated list. See linked commit.

[zambrovski]

I see. This seems to be because of Kotlin we are using where a varags seems to be treated as an array. My y proposed formatter was actually an array formatter. By the way, I still owe you a Kotlin example...

[janschaefer]

I see. Still even Java arrays are formatted as a comma-separated list. Is Kotlin using some other array type as Java? A Kotlin example would help me tracking down the issue :-)

[janschaefer]

Did you test your PR with Kotlin? Because your code uses instanceof Object[]. I assume that this will not work for the Kotlin Array type.

[zambrovski]

My actual implementation in Kotlin was:

import com.tngtech.jgiven.annotation.Format
import com.tngtech.jgiven.format.ArgumentFormatter
import com.tngtech.jgiven.format.PrintfFormatter

/**
 * Argument formatter dealing with varargs and displaying them as a comma-separated list of quoted strings.
 * Delegates on the Printf-Formatter for actual formatting.
 */
open class VarargsFormatter : ArgumentFormatter<Any> {

  private val printfFormatter = PrintfFormatter()

  override fun format(argumentToFormat: Any?, vararg formatterArguments: String?): String = if (argumentToFormat is Array<*>) {
    argumentToFormat.joinToString(", ") { printfFormatter.format(it, *formatterArguments) }
  } else {
    printfFormatter.format(argumentToFormat, *formatterArguments)
  }
}

/**
 * Annotation using the Vargarg Argument formatter.
 */
@MustBeDocumented
@Format(value = VarargsFormatter::class, args = ["\"%s\""])
@Retention(AnnotationRetention.RUNTIME)
@Target(AnnotationTarget.VALUE_PARAMETER, AnnotationTarget.ANNOTATION_CLASS, AnnotationTarget.FIELD)
annotation class QuotedVarargs