Add a migration plan for TestMethodProviders.

Author: dweiss

etc/junit4-missing-features.txt

@@ -5,7 +5,6 @@ Random implementation. Optionally (parameter?) enable verifying that this Random
 with other threads for reproducibility.
 
 4. Shuffled test execution order and seed annotations
-   - Test method execution order is randomized by default each run
    - @Seed on a class fixes the main seed, making execution fully deterministic
    - @Seeds / @Seed on a method pins a per-method seed for regression coverage
      while still running once with a fresh random seed
@@ -41,11 +40,6 @@ with other threads for reproducibility.
     - scaledRandomIntBetween() and multiplier() scale input sizes based on
       nightly vs. daily mode
 
-14. Custom test-method providers
-    - @TestMethodProviders({...}) substitutes the default (@Test-based) selector
-    - Implement TestMethodProvider to pick methods by any criteria (e.g. name
-      suffix convention)
-
 2. RandomizedTest base class and RandomizedContext
    - Extend RandomizedTest for convenient access to a per-test Random instance
    - Access the context directly via RandomizedContext.current()

randomizedtesting-jupiter/src/test/java/com/carrotsearch/randomizedtesting/jupiter/F999_RemovedFeatures.md

@@ -26,3 +26,24 @@ are run in discovery phase and execution contexts are not available then).
 ## Custom event listeners (`@Listeners`).
 
 * This feature is already part of JUnit5 (`TestExecutionListener`).
+
+## Custom test-method providers (`@TestMethodProviders()`)
+
+* JUnit5/ Jupiter offers many ways to discover tests dynamically. `@TestFactory`
+methods, templates, etc. While there is no one-to-one replacement, it should
+be possible to reimplement custom test providers with some minor refactorings.
+For example, if a `TestMethodProvider` was including all `test*` methods (JUnit3-style),
+you could write a `@TestFactory` in a common superclass and then just extend it. This
+test factory would something like this:
+```java
+@TestFactory
+Stream<DynamicTest> includeTestMethodsWithNoAnnotations() {
+    return Arrays.stream(getClass().getDeclaredMethods())
+        .filter(m -> m.getName().startsWith("test")
+                  && m.getParameterCount() == 0
+                  && !Modifier.isStatic(m.getModifiers()))
+        .map(m -> DynamicTest.dynamicTest(m.getName(), () -> {
+            m.invoke(this);
+        }));
+}
+```