JavaExercism/exercises/etl/src/test/java/EtlTest.java

import org.junit.Test;

import java.util.*;

import static org.junit.Assert.assertEquals;


public class EtlTest {
    private final Etl etl = new Etl();

    @Test
    public void testTransformOneValue() {
        Map<Integer, List<String>> old = new HashMap<Integer, List<String>>() {
            {
                put(1, Arrays.asList("A"));
            }
        };
        old = Collections.unmodifiableMap(old);

        Map<String, Integer> expected = new HashMap<String, Integer>() {
            {
                put("a", 1);
            }
        };
        expected = Collections.unmodifiableMap(expected);

        assertEquals(expected, etl.transform(old));
    }

    @Test
    public void testTransformMoreValues() {
        Map<Integer, List<String>> old = new HashMap<Integer, List<String>>() {
            {
                put(1, Arrays.asList("A", "E", "I", "O", "U"));
            }
        };
        old = Collections.unmodifiableMap(old);

        Map<String, Integer> expected = new HashMap<String, Integer>() {
            {
                put("a", 1);
                put("e", 1);
                put("i", 1);
                put("o", 1);
                put("u", 1);
            }
        };
        expected = Collections.unmodifiableMap(expected);

        assertEquals(expected, etl.transform(old));
    }

    @Test
    public void testMoreKeys() {
        Map<Integer, List<String>> old = new HashMap<Integer, List<String>>() {
            {
                put(1, Arrays.asList("A", "E"));
                put(2, Arrays.asList("D", "G"));
            }
        };
        old = Collections.unmodifiableMap(old);

        Map<String, Integer> expected = new HashMap<String, Integer>() {
            {
                put("a", 1);
                put("e", 1);
                put("d", 2);
                put("g", 2);
            }
        };
        expected = Collections.unmodifiableMap(expected);

        assertEquals(expected, etl.transform(old));
    }

    @Test
    public void testFullDataset() {
        Map<Integer, List<String>> old = new HashMap<Integer, List<String>>() {
            {
                put(1, Arrays.asList("A", "E", "I", "O", "U", "L", "N", "R", "S", "T"));
                put(2, Arrays.asList("D", "G"));
                put(3, Arrays.asList("B", "C", "M", "P"));
                put(4, Arrays.asList("F", "H", "V", "W", "Y"));
                put(5, Arrays.asList("K"));
                put(8, Arrays.asList("J", "X"));
                put(10, Arrays.asList("Q", "Z"));
            }
        };
        old = Collections.unmodifiableMap(old);

        Map<String, Integer> expected = new HashMap<String, Integer>() {
            {
                put("a", 1);
                put("b", 3);
                put("c", 3);
                put("d", 2);
                put("e", 1);
                put("f", 4);
                put("g", 2);
                put("h", 4);
                put("i", 1);
                put("j", 8);
                put("k", 5);
                put("l", 1);
                put("m", 3);
                put("n", 1);
                put("o", 1);
                put("p", 3);
                put("q", 10);
                put("r", 1);
                put("s", 1);
                put("t", 1);
                put("u", 1);
                put("v", 4);
                put("w", 4);
                put("x", 8);
                put("y", 4);
                put("z", 10);
            }
        };
        expected = Collections.unmodifiableMap(expected);

        assertEquals(expected, etl.transform(old));
    }
}