Expect (fail-at-end)

Question

Can somebody show me a complete minimal example for fail at end behaviour?

The docs I found says just:

expect.that(actual).isEqualTo(expected); // supplied by @Rule

Use case: I would like to have one test, multiple asserts (assertions on the same object, but I would like to see all assert failures, because the test itself is a long-running process).

Answer 1

Expect is intended to be used as a JUnit @Rule. You'll see in the source code that the AssertionError is thrown after the test finishes, in the rule's apply() method. Here's a simplified version of what it does:

public void evaluate() throws Throwable {
  // this invokes the test, collecting failures in gatherer
  base.evaluate();
  // after the test finishes the failures are collected and thrown
  if (!gatherer.getMessages().isEmpty()) {
    throw new AssertionError(gatherer.toString());
  }
}

There's an example usage of Expect in the unit tests (which isn't to say it shouldn't be better-documented elsewhere). Essentially, just add a line like:

@Rule public final Expect expect = Expect.create();

Then use expect.that(foo).... to make assertions about foo that don't cause the test to fail-fast, instead failing once the test is complete.