[Ivan Zerin provides a primer on mocking methods that contain generic return types.] There are several cases where construction when().thenReturn is not suitable during Unit tests. One of then generic return type. I have faced such issue, let's take a look. There is a method in interface declaration: public interface FooInterface { public Iterable getList(); ... } Implementation looks like this: public class Foo implements FooInterface { public List getList() { ... } ... } At first mocking of such method should not be something unusual: public class UnitTest { @Mock private FooInterface mockFoo; @Test public void someUnitTest() { ... List testList = generateTestList(); when(mockFoo.getList()) .thenReturn(testList); } } But this code won't compile with error: Cannot resolve method 'thenReturn(List). Seems to be some mistake, cause returned type are correct from the interface point of view. This error happening cause compiler can not gurantee that returned type of method getList() will be List. Actually return type of method getList() in this case is Iterable and this means "Return some Iterable object with any objects that extends SomeClass". Let's rename this type as 'X'. So when(mockFoo.getList()) will create object OngoingStubbing> and it has method thenReturn(Iterable). Compiler can not tell what type X before runtime and cannot perform safe cast from List to Iterable (we perfrom actuall call of method thenReturn(List)). Sounds a little tricky but let's assume that SomeClass is standard Java class Number. Then classes Integer and Double are both fulfill the criteria of List. Let's say that as return type of mock we will use List, in this case, compiler should be ready that actual work with code during runtime will be performed with List too, but it is clearly that cast from Double to Integer will be incorrect (try to cast double value 12.6 to int). You could argue that in the case of mockito compiler won't need to bother about the casting of returned type because call of original method would not produce anything, but it is known by mockito. From compiler point of view, it is only Java code, that should be checked for safety and correctness before compiling. Ok, so how we should deal with such cases in mockito? Use doReturn() method: doReturn(testList).when(mockFoo).getList(); Such expression is not type safe, so it were designed for exceprional cases, so use it only when you cannot use standart when().thenReturn(), which is the type-safe, elegant and more readable syntax.
CSS is essential for web development; however, it's difficult to get right for your average developer, who may have interests elsewhere in the stack. Read this article to avoid needling inconsistencies and adopt best practices.
Logback is one of the most popular logging frameworks for Java, but did you know you could configure it using Groovy? This guide walks you through the whole process.
Go is an excellent choice for building fast and scalable API's. The net/http package provides most of what you need, but augmented with the Gorilla Toolkit, you'll have an API up and running in no time. Learn how to build and secure a Go API with JSON Web Tokens and consume it via a modern UI built with React.
If you are using one of the many frameworks that say they are using JavaScript MVVM, you might not be using it the way it should be used. In this article, Dave Bush defines MVVM, analyzes its advantages, and provides some MVVM best practices to follow.
When trying to deploy a Node.js application to a remote server, how do we make it so that the user we've created (without sudo privilidges) to run/execute the application can see the necessary libraries needed to run our Node.js application? Read on and find out.
CORE
