java.lang.IllegalStateException: Could not find ApplicationContext, configure Grails correctly first

I have the following spock integration test for in grails 2.4.3, I have searched on google but didn't find anything understandable

@Mock([Product,Price])
class ProductViewerSpec extends IntegrationSpec {

ProductController productController = new ProductController()

void "Test the complete flow of retrieving and viewing a product"() {

    when: "The loadProducts method is executed to get list of products"
    String barCode = "1"
    String description = "testProduct"
    Set<Price> prices = new HashSet<Price>()
    Product product = new Product(barCode, description, prices)

    Price price1 = new Price(10 as BigDecimal).save(flush: true, failOnError: true)
    product.prices.add(price1)
    Price price2 = new Price(12 as BigDecimal).save(flush: true, failOnError: true)
    product.prices.add(price2)
    Price price3 = new Price(14 as BigDecimal).save(flush: true, failOnError: true)
    product.prices.add(price3)
    Price price4 = new Price(11 as BigDecimal).save(flush: true, failOnError: true)
    product.prices.add(price4)
    Price price5 = new Price(12 as BigDecimal).save(flush: true, failOnError: true)
    product.prices.add(price5)

    product.save(flush: true, failOnError: true)

    productController.productService.setPrices(product)

    List<Product> productList = productController.productService.loadProducts(product.getBarCode(), null)

    then: "All prices calculated and returned correctly"
    Product.count() == 1
    productList.size() == 1
    productList.get(0).barCode == barCode
    productList.get(0).description == description
    productList.get(0).prices.size() == 5
    productList.get(0).getAveragePrice() == 11.8 as BigDecimal
    productList.get(0).getLowestPrice() == 10 as BigDecimal
    productList.get(0).getHighestPrice() == 14 as BigDecimal
    productList.get(0).getIdealPrice() == 14.4 as BigDecimal
    productList.get(0).prices.id.contains(price1.id)
    productList.get(0).prices.id.contains(price2.id)
    productList.get(0).prices.id.contains(price3.id)
    productList.get(0).prices.id.contains(price4.id)
    productList.get(0).prices.id.contains(price5.id)
}
}

I am getting following error when I run grails test-app from command line.

| Compiling 1 source files
| Compiling 1 source files.
| Running 5 integration tests...
| Running 5 integration tests... 1 of 5
| Failure:  com.prizypricer.core.ProductViewerSpec
|  java.lang.IllegalStateException: Could not find ApplicationContext, configure Grails correctly first
at grails.util.Holders.getApplicationContext(Holders.java:97)
at         grails.test.spock.IntegrationSpec.$spock_initializeSharedFields(IntegrationSpec.groovy:41)
| Failure:  com.prizypricer.core.ProductLoaderSpec
|  java.lang.IllegalStateException: Could not find ApplicationContext, configure Grails correctly first
at grails.util.Holders.getApplicationContext(Holders.java:97)
at     grails.test.spock.IntegrationSpec.$spock_initializeSharedFields(IntegrationSpec.groovy:41)
| Completed 1 integration test, 0 failed in 0m 0s

Can anyone tell what is wrong?