junit-team/junit5 · error · JUnitException

File [%s] could not be read

Error message

File [%s] could not be read

What it means

Thrown by the openFile(String) path source of CsvFileArgumentsProvider when Files.newInputStream(Path.of(path)) raises an IOException. The message names the path that could not be read and chains the IOException as cause. This is distinct from the classpath resource check, which fails earlier with a different message.

Source

Thrown at junit-jupiter-params/src/main/java/org/junit/jupiter/params/provider/CsvFileArgumentsProvider.java:178

		private static final DefaultInputStreamProvider INSTANCE = new DefaultInputStreamProvider();

		@Override
		public InputStream openClasspathResource(Class<?> baseClass, String path) {
			Preconditions.notBlank(path, () -> "Classpath resource [" + path + "] must not be null or blank");
			//noinspection resource (closed elsewhere)
			InputStream inputStream = baseClass.getResourceAsStream(path);
			return Preconditions.notNull(inputStream, () -> "Classpath resource [" + path + "] does not exist");
		}

		@Override
		public InputStream openFile(String path) {
			Preconditions.notBlank(path, () -> "File [" + path + "] must not be null or blank");
			try {
				return Files.newInputStream(Path.of(path));
			}
			catch (IOException e) {
				throw new JUnitException("File [" + path + "] could not be read", e);
			}
		}

	}

}

View on GitHub (pinned to f070c699a0)

Solutions

1. Use an absolute path or verify the working directory; for classpath files prefer resources = ... instead of files = ...
2. Confirm the file exists and is a regular file: Files.isRegularFile(Path.of(path)).
3. Fix filesystem permissions so the test process can read the file.
4. Move the data into src/test/resources and reference it via resources to avoid path issues.

Example fix

// before
@CsvFileSource(files = "testdata/input.csv")

// after (classpath)
@CsvFileSource(resources = "/testdata/input.csv")
// or absolute path
@CsvFileSource(files = "/abs/path/to/input.csv")

// Verify the file exists and is readable before the test runs
Path p = Path.of(csvFilePath);
if (!Files.isRegularFile(p) || !Files.isReadable(p))
    throw new IllegalArgumentException("CSV file not readable: " + p);

static boolean isReadableCsvFile(String path) {
    Path p = Path.of(path);
    return Files.isRegularFile(p) && Files.isReadable(p);
}

When it happens

Trigger: Providing @CsvFileSource(files = "...") with a path that does not exist, is a directory, or is not readable by the process. The openFile implementation catches IOException and wraps it as JUnitException.

Common situations: Relative file path resolved against an unexpected working directory. Missing or moved test data file. Permission denied on the file in CI. Path points to a directory rather than a file.

Related errors

• The charset supplied in %s is invalid
• Timeout duration is not in the expected format (<number> [ns
• Failed to parse CSV input configured via %s
• %s must be used with an annotation of type %s
• Assumption failed

AI-assisted analysis of junit-team/junit5@f070c699a0 (2026-08-11). Data as JSON: /api/errors/9eea5dade05d5eb8. Report an issue: GitHub.