Fix Spack failing test

Signed-off-by: Paolo Di Tommaso <paolo.ditommaso@gmail.com>

Author: pditommaso

modules/nextflow/src/main/groovy/nextflow/spack/SpackCache.groovy

@@ -299,7 +299,7 @@ class SpackCache {
     }
 
     @PackageScope
-    int runCommand( String cmd ) {
+    void runCommand( String cmd ) {
         log.trace """spack env create
                      command: $cmd
                      timeout: $createTimeout""".stripIndent()
@@ -317,7 +317,6 @@ class SpackCache {
             msg += err.toString().trim().indent('    ')
             throw new IllegalStateException(msg)
         }
-        return status
     }
 
     /**

modules/nextflow/src/test/groovy/nextflow/spack/SpackCacheTest.groovy

@@ -117,7 +117,7 @@ class SpackCacheTest extends Specification {
         then:
         1 * cache.spackPrefixPath(ENV) >> PREFIX
         0 * cache.isYamlFilePath(ENV)
-        1 * cache.runCommand( "spack env activate $PREFIX ; spack install -y ; spack env deactivate" )
+        1 * cache.runCommand( "spack env activate $PREFIX ; spack install -y ; spack env deactivate" ) >> null
         result == PREFIX
 
         when: