java - Spock unit test, groovy leftshift assignment is throwing a SpockExecutionException: Data provider has no data -

i'm writing spock unit test , following error thrown when try supply data provider dynamically using groovy collect

spockexecutionexception: data provider has no data 

here simplest case can provide throws error:

import spock.lang.shared import spock.lang.specification  class sampletest extends specification {      @shared     def somearray      void setup() {         somearray = ['a','b','c']     }      def "ensure 'data provider has no data' not thrown"() {          expect:         columna == columnb          where:         [columna, columnb] << somearray.collect { value -> [value, value] }     } } 

the groovy code seems work. here's test on groovy console:

def somearray = ['a','b','c'] def test = somearray.collect { value -> [value, value] } println test  [[a, a], [b, b], [c, c]] 

what misunderstanding?

i'm using:

• groovy version 2.2.1
• spock version 0.7-groovy-2.0
• junit version 4.12

use setupspec() instead of setup() access @shared variable way want to, indicated in @shared documentation. alternatively, can initialize shared variable during it's declaration.

import spock.lang.*  class sampletest extends specification {      @shared somearray      // similar using     // @shared somearray = ['a','b','c']     // use above instead of setupspec() if required     // setupspec() invoked before test case invoked     void setupspec() {         somearray = ['a','b','c']     }      def "ensure 'data provider has no data' not thrown"() {         expect:         columna == columnb          where:         [columna, columnb] << somearray.collect { [it, it] }     } }