Add support for Junit 5.4's @DisplayNameGeneration generators

[fbricon]

Following up on #446, @DisplayNameGeneration generators from Junit 5.4 should be supported. See https://junit.org/junit5/docs/5.4.0/user-guide/index.html#writing-tests-display-name-generator

import java.lang.reflect.Method;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.DisplayNameGeneration;
import org.junit.jupiter.api.DisplayNameGenerator;
import org.junit.jupiter.api.Nested;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

class DisplayNameGeneratorDemo {

    @Nested
    @DisplayNameGeneration(DisplayNameGenerator.ReplaceUnderscores.class)
    class A_year_is_not_supported {

        @Test
        void if_it_is_zero() {
        }

        @DisplayName("A negative value for year is not supported by the leap year computation.")
        @ParameterizedTest(name = "For example, year {0} is not supported.")
        @ValueSource(ints = { -1, -4 })
        void if_it_is_negative(int year) {
        }

    }

    @Nested
    @DisplayNameGeneration(IndicativeSentences.class)
    class A_year_is_a_leap_year {

        @Test
        void if_it_is_divisible_by_4_but_not_by_100() {
        }

        @ParameterizedTest(name = "Year {0} is a leap year.")
        @ValueSource(ints = { 2016, 2020, 2048 })
        void if_it_is_one_of_the_following_years(int year) {
        }

    }

    static class IndicativeSentences extends DisplayNameGenerator.ReplaceUnderscores {

        @Override
        public String generateDisplayNameForClass(Class<?> testClass) {
            return super.generateDisplayNameForClass(testClass);
        }

        @Override
        public String generateDisplayNameForNestedClass(Class<?> nestedClass) {
            return super.generateDisplayNameForNestedClass(nestedClass) + "...";
        }

        @Override
        public String generateDisplayNameForMethod(Class<?> testClass, Method testMethod) {
            String name = testClass.getSimpleName() + ' ' + testMethod.getName();
            return name.replace('_', ' ') + '.';
        }

    }

}

Should yield

+-- DisplayNameGeneratorDemo [OK]
  +-- A year is not supported [OK]
  | +-- A negative value for year is not supported by the leap year computation. [OK]
  | | +-- For example, year -1 is not supported. [OK]
  | | '-- For example, year -4 is not supported. [OK]
  | '-- if it is zero() [OK]
  '-- A year is a leap year... [OK]
    +-- A year is a leap year if it is divisible by 4 but not by 100. [OK]
    '-- A year is a leap year if it is one of the following years. [OK]
      +-- Year 2016 is a leap year. [OK]
      +-- Year 2020 is a leap year. [OK]
      '-- Year 2048 is a leap year. [OK]

[jdneo]

We will see this enhancement in the next release working with the VS Code new testing API:

[jdneo]

0.31.0 is released! 🎉