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 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
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package org.apache.james.mailbox.elasticsearch.json;

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

import org.junit.Test;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableSet;

public class SubjectsTest {

    @Test
    public void fromShouldThrowWhenSetIsNull() {
        assertThatThrownBy(() -> Subjects.from(null))
            .isInstanceOf(NullPointerException.class)
            .hasMessage("'subjects' is mandatory");
    }

    @Test
    public void serializeShouldReturnEmptyWhenEmptySet() {
        Subjects subjects = Subjects.from(ImmutableSet.of());

        assertThat(subjects.serialize()).isEmpty();
    }

    @Test
    public void serializeShouldNotJoinWhenOneElement() {
        String expected = "subject";
        Subjects subjects = Subjects.from(ImmutableSet.of(expected));

        assertThat(subjects.serialize()).isEqualTo(expected);
    }

    @Test
    public void serializeShouldJoinWhenMultipleElements() {
        String subject = "subject";
        String subject2 = "subject2";
        String subject3 = "subject3";

        String expected = Joiner.on(" ").join(subject, subject2, subject3);

        Subjects subjects = Subjects.from(ImmutableSet.of(subject, subject2, subject3));

        assertThat(subjects.serialize()).isEqualTo(expected);
    }
}
