Use of mock objects for testing purposes

[bonaparten]

In order to test a unit of the ohsome API, we need to create all the java objects needed for the test even if the dependencies themselves are not the purpose of the test. Using some frameworks (e.g. Mockito) in order to create mock objects could make tests more flexible and easier to handle.
There are lots of use cases where creating mock objects could make things easier. One simple example:

public class GeometryBuilderTest {

  @Mock
  InputProcessor mockProc;
  
  // Since we mock the InputProcessor object we don't need to define a ProcessingData object at all
  // private ProcessingData processingData = new ProcessingData(null, null);

  @Test(expected = BadRequestException.class)
  public void createPolygonFromGeoJsonWithWrongFormat() {
    String geoJson =
        "{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"MultiPolygon\",\"coordinates\":"
            + "[[[[8.2944706,49.4313443],[8.2943343,49.4311946],[8.2942287,49.4313051],"
            + "[8.2942929,49.4313993],[8.2940648,49.4314931],[8.2931602,49.4328216],"
            + "[8.2933214,49.4329125],[8.2936734,49.4330121],[8.2940745,49.4331354],"
            + "[8.2950478,49.4317345],[8.2944706,49.4313443]]]]}]}";
    // InputProcessor inputProcessor = new InputProcessor(processingData);
    // geomBuilder.createGeometryFromGeoJson(geoJson, inputProcessor);
    geomBuilder.createGeometryFromGeoJson(geoJson, mockProc);
  }
}