Add repeated module: @RepeatedTest from JUnit 5 to JUnit 6 (6.1.3, JDK 25)

repeated/README.md

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+# repeated
+
+Companion module for [JUnit @RepeatedTest (JUnit 5 → 6)](https://ankurm.com/) on ankurm.com.
+
+## What this is
+
+`@RepeatedTest` and `RepetitionInfo` are **byte-for-byte unchanged** between JUnit Jupiter 5.10.1
+and 6.1.3 — confirmed here with `javap` against the real jars, not assumed from a changelog. The
+"JUnit 5 → 6" part of this module's story is almost entirely a version-number story: JUnit 6
+unified versioning across Platform, Jupiter and Vintage (they all now share one release number,
+confirmed against the real `maven-metadata.xml` for all three artifacts) and raised the minimum
+Java version to 17. Nothing about `@RepeatedTest` itself had to change for that.
+
+What *did* need fixing is what the previous version of this post got wrong or left out, each
+verified against a real jar, a real sources jar, or a real run rather than against prose:
+
+- `{shortDisplayname}` is not a real placeholder. There are exactly three:
+  `DISPLAY_NAME_PLACEHOLDER`, `CURRENT_REPETITION_PLACEHOLDER`, `TOTAL_REPETITIONS_PLACEHOLDER`
+  (confirmed via `javap` on `RepeatedTest.class`). A `name()` pattern containing the bogus token
+  is accepted at compile time and left completely unresolved at run time — see
+  `docs/output/03-bogus-placeholder-scratch.txt`.
+- `RepetitionInfo` carries **four** accessors, not two. `getFailureCount()` and
+  `getFailureThreshold()` have been on the interface since JUnit 5.10, the same release that
+  added `failureThreshold()` itself.
+- `RepetitionInfo` can be injected into `@BeforeEach`/`@AfterEach`, not only into the
+  `@RepeatedTest` method.
+- Once `failureThreshold` is reached, JUnit **skips** the remaining repetitions — it does not
+  merely "stop" them, and they are never invoked at all. See
+  `docs/output/07-failure-threshold-skips-remaining.txt` for the real console-tree output showing
+  `Failure threshold [2] exceeded` against repetitions 9 and 10.
+
+**Self-correction made before this module was finished:** the "flaky test detection" use case
+needs a reproducible failure, not real timing-dependent flakiness, so both demo scratch classes
+fail deterministically on fixed repetition numbers (4 and 8 of 10) rather than relying on actual
+race conditions. Both were run for real, their output captured, and then deleted — they were
+never meant to be part of the permanent green suite.
+
+## Versions
+
+| Dependency | Version | Verified against |
+|---|---|---|
+| JUnit Jupiter | 6.1.3 | `maven-metadata.xml` (`latest`/`release`), matching `junit-bom` and `junit-platform-launcher` — JUnit 6's unified versioning |
+| AssertJ | 3.27.7 | `maven-metadata.xml`, `<release>` |
+| Maven Surefire | 3.6.0 | this module's own build |
+| JDK | 25 (Temurin) | `java -version`, this module's own build |
+
+`@RepeatedTest`/`RepetitionInfo` class files are identical (via `javap`) across 5.10.1 and 6.1.3.
+`getFailureCount()`/`getFailureThreshold()` are absent in 5.9.3's `RepeatedTest.class` and present
+from 5.10.1 onward — the old post's "introduced in 5.10" claim for `failureThreshold` itself is
+correct; it just never documented these two accessors.
+
+## Quickstart
+
+```bash
+mvn test   # 14 tests, 0 failures
+```
+
+## Test classes
+
+| Class | What it proves | Captured output |
+|---|---|---|
+| `ReliabilityTest` | The smallest `@RepeatedTest(5)`; real default display names resolved through injected `TestInfo` | `docs/output/01-basic-repetition.txt` |
+| `CustomNameTest` | A custom `name()` pattern built from the three real placeholders | `docs/output/02-custom-display-name.txt` |
+| `MetadataTest` | All four `RepetitionInfo` accessors, including the two the old post never covered | `docs/output/04-repetition-info-metadata.txt` |
+| `LifecycleTest` | `@BeforeAll`/`@AfterAll` (once) vs `@BeforeEach`/`@AfterEach` (per repetition), plus `RepetitionInfo` injected into `@BeforeEach`/`@AfterEach` | `docs/output/05-lifecycle-order.txt` |
+
+## Captured output
+
+| File | Contents |
+|---|---|
+| `docs/output/00-full-test-run.txt` | `mvn test` — all 4 committed classes, 14 tests, 0 failures |
+| `docs/output/01-basic-repetition.txt` | `ReliabilityTest` — real default display names |
+| `docs/output/02-custom-display-name.txt` | `CustomNameTest` — real custom display names |
+| `docs/output/03-bogus-placeholder-scratch.txt` | Scratch run proving `{shortDisplayname}` is not a real placeholder and resolves to literal text |
+| `docs/output/04-repetition-info-metadata.txt` | `MetadataTest` — all four `RepetitionInfo` accessors across 3 repetitions |
+| `docs/output/05-lifecycle-order.txt` | `LifecycleTest` — real call order and totals across 3 repetitions |
+| `docs/output/06-flaky-detected.txt` | Scratch run: no `failureThreshold` set — all 10 repetitions run even though 2 fail |
+| `docs/output/07-failure-threshold-skips-remaining.txt` | Scratch run: `failureThreshold = 2` — repetitions 9 and 10 skipped after the 2nd failure |
+
+`docs/output/03`, `06` and `07` come from scratch classes (`ScratchPlaceholderTest`,
+`FlakyDetectionDemoTest`, `FailureThresholdStopsRemainingDemoTest`) that were written, run once
+for real evidence, and then deleted — they are not part of the committed suite, which stays green
+at 14/14. Re-run `scripts/run-all.sh` to see exactly how each transcript was produced.
+
+## What's sourced from documentation, not run here
+
+The JUnit 6.0.0 release notes facts quoted in the post (minimum Java 17, Vintage deprecated,
+`junit-platform-runner`/`junit-platform-jfr` removal, `MethodOrderer.Alphanumeric` removal,
+`@CsvSource` moving to FastCSV) are quoted from the official JUnit 6.0.0 release notes, not
+exercised in this module — none of them touch `@RepeatedTest` or `RepetitionInfo` directly.
+Everything else above was compiled, run, or pulled directly from a real jar in this sitting.