I often forget the processes that are often used in JUnit 5, so I will write them as a memorandum.

What you can do with standard functions. I can't do it, so make a note of the case where you need to make your own.

1. What you want to do

1-1. Preparation

Copy of data

1-2. Test verification

bool value comparison
String comparison
Partial comparison of String
File existence check
Check file contents
Check the contents of the exception

1-3. Post-processing

Delete data

1-4. Others

2. Basic knowledge

2-1. Basic knowledge

In JUnit5 (Jupiter), write the error message when the test fails in the last argument.

2-2. Reference URL

3.TIPS

3-1. File lock

Lock the target file so that it cannot be read.


    try (
        FileChannel fc =
            FileChannel.open(Paths.get(""), StandardOpenOption.CREATE, StandardOpenOption.WRITE);
        FileLock lock = fc.tryLock()) {
      //Operation after lock acquisition
    } catch (Exception e) {
      //Lock acquisition failure
    }

3-2. File comparison

If the file size is small, use commons-io for the following.

    assertThat(FileUtils.readFileToString(file1, "UTF-8"),
        is(FileUtils.readFileToString(file2, "UTF-8")));

[Personal] JUnit5 memorandum memo (work in progress)