@Test
void writePropertiesFile_merging() throws IOException, URISyntaxException {

    // set up a temp file with the current contents
    setupCurrentFile(TEST_PROPERTIES, PROPERTIES);
    final Properties properties = new Properties();
    properties.putAll(ImmutableMap.of("key1", "value1", "key2", "value2"));
    WriterHelper.writePropertiesFile(testProjectDir, documentFileUtils, properties, TEST_PROPERTIES);
    assertPropertiesContents(
            new HashMap<>(
                    ImmutableMap.<String, String>builder()
                            .put("key1", "value1")
                            .put("key2", "value2")
                            .put("key3", "value3")
                            .put("key4", "value4")
                            .build()
            )
    );
}