Support proto enum aliases: Update CHANGELOG and add documentation

Author: nymanjens

CHANGELOG.md

@@ -7,6 +7,8 @@
 - Added support for repeated annotations to [`TestParameterValuesProvider.Context`](
   https://google.github.io/TestParameterInjector/docs/latest/com/google/testing/junit/testparameterinjector/TestParameterValuesProvider.Context.html)
 - Converting incorrectly YAML-parsed booleans back to their enum values when possible
+- Support enum aliases (defined as static fields on the enum), and in particular
+  Protocol Buffer enum aliases
 
 ## 1.15
 

junit4/src/main/java/com/google/testing/junit/testparameterinjector/ParameterValueParsing.java

@@ -54,6 +54,9 @@ static <E extends Enum<E>> Enum<?> parseEnum(String str, Class<?> enumType) {
     try {
       return Enum.valueOf((Class<E>) enumType, str);
     } catch (IllegalArgumentException e) {
+      // The given name was not a valid enum value. However, the enum might have an alias to one of
+      // its values defined as static field. This happens for example (via code generation) in the
+      // case of Protocol Buffer aliases (see the allow_alias option).
       Optional<Enum<?>> enumValue = maybeGetStaticConstant(enumType, str);
       if (enumValue.isPresent()) {
         return enumValue.get();

junit5/src/main/java/com/google/testing/junit/testparameterinjector/junit5/ParameterValueParsing.java

@@ -54,6 +54,9 @@ static <E extends Enum<E>> Enum<?> parseEnum(String str, Class<?> enumType) {
     try {
       return Enum.valueOf((Class<E>) enumType, str);
     } catch (IllegalArgumentException e) {
+      // The given name was not a valid enum value. However, the enum might have an alias to one of
+      // its values defined as static field. This happens for example (via code generation) in the
+      // case of Protocol Buffer aliases (see the allow_alias option).
       Optional<Enum<?>> enumValue = maybeGetStaticConstant(enumType, str);
       if (enumValue.isPresent()) {
         return enumValue.get();