回归测试框架雏形：JRegress.recording() 记录运行结果， JRegress.matching() 比较实际和上次记录的结果

JRegressTest.java

package jregress;

import org.hamcrest.BaseMatcher;
import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.junit.Test;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.StandardOpenOption;

public class JRegressTest {

    //All tests can share the the sam regress instance
    public static JRegress regress = JRegress.recording("");

    //public static JRegress regress = JRegress.matching();

    public int square(int i) {
        return i * i;
    }

    @Test
    public void should_record_expected_result_and_compare_with_actual() {
        assertRegress(square(2), JRegress.recording("sq").matching(2));
        assertRegress(square(2), JRegress.matching("sq").matching(2));
        assertRegress(5, JRegress.matching("sq").matching(2));
    }

    public static void assertRegress(Object actual, Matcher<String> matcher) {
        org.junit.Assert.assertThat(actual.toString(), matcher);
    }

    interface Storage {
        String get(String key);
        void put(String key, String value);
    }

    public static class FileStorage implements Storage {
        private final File path;

        public FileStorage(File path) {
            this.path = path;
        }

        public FileStorage() {
            this(new File("."));
        }

        @Override
        public String get(String key) {
            try {
                return new String(Files.readAllBytes(new File(path, key).toPath()));
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }

        @Override
        public void put(String key, String value) {
            try {
                Files.write(new File(path, key).toPath(), value.getBytes(), StandardOpenOption.CREATE);
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    static class JRegress {
        private final String id;
        private final Storage storage;

        public JRegress(String id, Storage storage) {
            this.id = id;
            this.storage = storage;
        }

        public JRegress(String id) {
            this(id, defaultStorage());
        }

        public Matcher<String> recording(Object input) {
            return new RecordingMatcher(hash(input), storage);
        }

        public Matcher<String> matching(Object input) {
            return new StringMatcher(storage.get(hash(input)));
        }

        public static JRegress recording(String id, Storage storage) {
            return new JRegress(id, storage) {
                @Override
                public Matcher<String> matching(Object input) {
                    return recording(input);
                }
            };
        }

        public static JRegress matching(String id) {
            return new JRegress(id, defaultStorage());
        }

        public static JRegress recording(String id) {
            return recording(id, defaultStorage());
        }

        protected String hash(Object input) {
            return id + input.hashCode();
        }


        private static Storage defaultStorage() {
            return new FileStorage();
        }
    }



    private static class RecordingMatcher extends BaseMatcher<String> {
        private final String key;
        private final Storage storage;

        private RecordingMatcher(String key, Storage storage) {
            this.key = key;
            this.storage = storage;
        }

        @Override
        public void describeTo(Description description) {
        }

        @Override
        public boolean matches(Object o) {
            storage.put(key, o.toString());
            return true;
        }
    }

    private static class StringMatcher extends BaseMatcher<String> {
        private final String expected;

        private StringMatcher(String expected) {
            this.expected = expected;
        }

        @Override
        public void describeTo(Description description) {
        }

        @Override
        public boolean matches(Object o) {
            return expected.equals(o);
        }
    }
}