Core: TableConverter extracts child object values but not headers

[outadoc]

Hi! I'd like to report a bug I encountered while trying out Cucumber on my freshly-converted Kotlin Android application. I'm not entirely sure if this is a bug with Cucumber or Kotlin, so I'll let you judge.

Steps to reproduce

• Given TimeoLine.kt

data class TimeoLine (val id: String, val name: String, val direction: TimeoDirection, val networkCode: Int = 147, val color: String = "#34495E") {
    override fun toString(): String = name
}

• Given TimeoDirection.kt

data class TimeoDirection (var id: String, var name: String) {
    override fun toString(): String = "$id - $name"
}

nb: As you can see, TimeoLine contains a TimeoDirection as a property named direction

• Call DataTable.create() on a List<TimeoLine>

Expected behavior

The function returns a table that looks like this:

id	name	direction	networkCode	color
TRAM	Tram	A - Ifs Grace de Dieu	147	#ff3300
...	...	...	...	...

Observed behavior

cucumber.runtime.CucumberException: Table is unbalanced: expected 5 column(s) but found 6.
    at cucumber.api.DataTable.<init>(DataTable.java:63)
    at cucumber.runtime.table.TableConverter.createDataTable(TableConverter.java:272)
    at cucumber.runtime.table.TableConverter.toTable(TableConverter.java:258)
    at cucumber.api.DataTable.create(DataTable.java:45)
    at cucumber.api.DataTable.create(DataTable.java:31)
    at fr.outadev.android.transport.timeo.ParseStepDefinitions.iGetTheFollowingLines(ParseStepDefinitions.kt:65)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at cucumber.runtime.Utils$1.call(Utils.java:37)
    at cucumber.runtime.Timeout.timeout(Timeout.java:13)
    at cucumber.runtime.Utils.invoke(Utils.java:31)
    at cucumber.runtime.java.JavaStepDefinition.execute(JavaStepDefinition.java:38)
    at cucumber.runtime.StepDefinitionMatch.runStep(StepDefinitionMatch.java:37)
    at cucumber.runtime.Runtime.runStep(Runtime.java:299)
    [...]

By playing a bit with the DataTable conversion, you'll see ComplexTypeWriter extracts all the values in the object, including the members of TimeoDirection; but it only extracts the headers for the properties of the parent object (TimeoLine). It also causes some not-failing-but-extremely-confusing-behavior in diffs.

• Runtime: java-8-openjdk
• Lib version: info.cukes:cucumber-java:1.2.4

[mgurov]

Could be related to #1042

[outadoc]

I'm not sure how to compile the fix to test it, but it sure looks like that could be it.

[outadoc]

If anyone seeing this knows of a workaround in the mean time, I'd be really interested!

[mpkorstanje]

There are two bugs in here. One being that that ComplexTypeWriter goes out of alignment when dealing with nested complex types. E.g. {a: "A", b: { bb: "BB"}, c: "C"} the other being that datatables were not designed to handle the nested complex types like b at all.

The first will be fixed with #1042.

The second will need some discussion.

I reckon the proper way would be to use the string representation of b. E.g:

{
  a: "A", 
  b: { 
    b1: "B1",
    b2: "B2",
    toString() {
       return this.b1 "-" + this.b2;
    }
  }, 
  c: "C"
}

| a | b     | c | 
| A | B1-B2 | C |

When dealing with lists, dates and other basic types we'd need to use the existing converters. E.g:

{
  a: "A", 
  b: ["B1", "B2"]
  c: "C"
}

| a | b      | c | 
| A | B1, B2 | C |

None of this seems to be supported by the current setup though. I'm that deeply into XStream. If anybody feels like figuring this out please do!

[mpkorstanje]

As it turns out I was mistaken. To achieve the desired result you have to add a converter that tells Cucumber how to present your object in a table. This should also prevent any table imbalances.

@XStreamConverter(TimeoDirectionConvertor::class)
data class TimeoDirection (var id: String, var name: String) {
    override fun toString(): String = "$id - $name"
}

class TimeoDirectionConvertor : SingleValueConverter {

    override fun toString(p0: Any?): String = p0.toString()

    override fun fromString(p0: String?): Any = {
        val (id, name) = p0!!.split(" - ");
        TimeoDirection(id, name)
    }

    override fun canConvert(p0: Class<*>?): Boolean = TimeoDirection::class.java.isAssignableFrom(p0)
}

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.