Can't read Mocked Java.io.Reader - junit

Question

I want to test following code with Mockito:
public static String funcToTest(String query) throws Exception {
String url = Config.getURL(serviceName);
HttpClient client = new HttpClient();
HttpMethod method = new GetMethod(url);
String resultantString= "";
method.setQueryString(URIUtil.encodeQuery(query));
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
Reader reader = new InputStreamReader(method
.getResponseBodyAsStream());
int charValue = 0;
StringBuffer sb = new StringBuffer(1024);
while ((charValue = reader.read()) != -1) {
sb.append((char) charValue);
}
resultantString = sb.toString();
}
method.releaseConnection();
return resultantString;
}
I created the test like following:
#Test
public void testFunc() throws Exception{
HttpMethod method = Mockito.mock(HttpMethod.class);
InputStream inputStream = Mockito.mock(InputStream.class);
Reader reader = Mockito.mock(Reader.class);
when(method.getResponseBodyAsStream()).thenReturn(inputStream);
PowerMockito.whenNew(Reader.class).withArguments(eq(inputStream)).thenReturn(reader);
Mockito.when(reader.read()).thenReturn((int)'1', -1);
String actualResult = cls.funcToTest("");
String expected = "1";
assertEquals(expected, actualResult);
}
But the reader.read() method is not returning 1. Instead it always returns -1. How should I mock Reader so that read() method will return something else other than -1.
Thanks.

Answer 1

First of all , your test code is doing lots of .class mocking to mock function local variables / references. Mocking is for class dependencies and not for function local variables.
As written, you can't test your function funcToTest with mocking alone. You need to rewrite this function if not willing to use real objects for - HttpMethod & Reader.
You need to remove object creation code with new outside this function if you wish to mock calls on those objects and replace code of new with this get method. e.g.
protected HttpMethod getHttpMethod(String Url){
return new GetMethod(url);
}
Also, I don't see you mocking this line for a fake URL - it seems necessary for unit testing.
String url = Config.getURL(serviceName);
After taking object creation code outside your function, you need to create a new class than extends your SUT ( Subject Under Test ) and you override these methods ( getHttpMethod) to provide fake/mocked instances.
You need to write similar method to get Reader instance.
Then you test this new class - extended from your SUT since object creation logic need not to be tested.
Without taking object creation code outside the function, I don't see a way of mocking it by mockito.
Hope it helps !!

Answer 2

It must work, I'm sorry what make you slightly confused )
// annotations is very important, cls I your tested class name, i assume cls is yours
#RunWith(PowerMockRunner.class)
#PrepareForTest({cls.class})
public class PrinterTest {
#Test
public void print() throws Exception {
String url = "";
GetMethod method = Mockito.mock(GetMethod.class);
InputStream inputStream = Mockito.mock(InputStream.class);
InputStreamReader reader = Mockito.mock(InputStreamReader.class);
Mockito.when(method.getResponseBodyAsStream()).thenReturn(inputStream);
//forgot about it )
PowerMockito.whenNew(GetMethod.class).withArguments(eq(url)).thenReturn(method);
PowerMockito.whenNew(InputStreamReader.class).withArguments(eq(inputStream)).thenReturn(reader);
Mockito.when(reader.read()).thenReturn((int) '1', -1);
when(method.getStatusCode()).thenReturn(HttpStatus.SC_OK);
String actualResult = cls.funcToTest(url);
String expected = "1";
assertEquals(expected, actualResult);
}
}