Java style regular expressions kata in Java

RegexTest.java

package com.mathieupauly.regexkata;

import org.junit.Test;

import static org.assertj.core.api.Assertions.assertThat;

public class RegexTest {
    @Test
    public void selfMatching() {
      assertThat("a".matches("a")).isEqualTo(true);
    }

    @Test
    public void selfMatchingOnMulticharacters() {
        assertThat("abc".matches("abc")).isEqualTo(true);
    }

    @Test
    public void matchOr() {
        assertThat("a".matches("a|b")).isEqualTo(true);
    }

    @Test
    public void orNothing() {
        assertThat("a".matches("a|")).isEqualTo(true);
        assertThat("a".matches("|a")).isEqualTo(true);
    }

    @Test
    public void dot() {
        assertThat("a".matches(".")).isEqualTo(true);
    }

    @Test
    public void orHasLowerPrecedenceThanSequence() {
        assertThat("ab".matches("ab|xy")).isEqualTo(true);
    }

}