Mock a method in the same class being tested

Question

I want to mock a method in the same class that I am testing.

ClassA {
   function hardToTest($arg) {
      // difficult to test code
   }

   function underTest() {
      return $this->hardToTest('foo');
   }
}

I was thinking that I could use reflection to do this, but maybe it is just a sign that I should move hardToTest into another object.

Answer 1

This test will succeed if underTest() passes 'foo' to hardToTest(). This is known as a partial mock in PHPUnit's documentation because you are mocking only some of the methods.

ClassATest {     function testUnderTest() {         $mock = $this->getMock('ClassA', ['hardToTest']);         $mock->expects($this->once())              ->method('hardToTest')              ->with('foo');         $mock->underTest();     } } 

I agree with your instincts that this need may be a code smell telling you that this class is doing too much.

PHPUnit 5.4+

Since getMock() was deprecated in 5.4, use getMockBuilder() instead:.

$mock = $this->getMockBuilder('ClassA')              ->setMethods(['hardToTest'])    // onlyMethods in 8.4+              ->ge‌​tMock();