LogFileProvider { public Collection<String> getLogFileNames() { Collection<File> files = getLogFiles(LOG_PATH); return createFileNames(files); }  Collection<String> getLogFileNames(); String getLogContent(final String fileName);  }
@Test public void testGetLogFileNames() { Collection<File> files = getFileCollection(); Collection<String> expectedNames = new ArrayList<>(); expectedNames.add("a"); expectedNames.add("b"); expectedNames.add("c"); given(fileUtils.getFilesWithExtension(LOG_PATH, LOG_EXTENSION)).willReturn(files); Collection<String> result = underTest.getLogFileNames(); assertEquals(expectedNames, result); }