Add helper functions to convert api Genre to domain entity.

Signed-off-by: Yahor Berdnikau <egorr.berd@gmail.com>

ultrasonic/src/main/java/org/moire/ultrasonic/domain/Genre.java

@@ -31,7 +31,25 @@ public class Genre implements Serializable
 		this.index = index;
 	}
 
-	@Override
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+
+        Genre genre = (Genre) o;
+
+        if (name != null ? !name.equals(genre.name) : genre.name != null) return false;
+        return index != null ? index.equals(genre.index) : genre.index == null;
+    }
+
+    @Override
+    public int hashCode() {
+        int result = name != null ? name.hashCode() : 0;
+        result = 31 * result + (index != null ? index.hashCode() : 0);
+        return result;
+    }
+
+    @Override
 	public String toString()
 	{
 		return name;

ultrasonic/src/main/kotlin/org/moire/ultrasonic/data/APIGenreConverter.kt

@@ -0,0 +1,13 @@
+// Collection of functions to convert api Genre entity to domain entity
+@file:JvmName("ApiGenreConverter")
+package org.moire.ultrasonic.data
+
+import org.moire.ultrasonic.domain.Genre
+import org.moire.ultrasonic.api.subsonic.models.Genre as APIGenre
+
+fun APIGenre.toDomainEntity(): Genre = Genre().apply {
+    name = this@toDomainEntity.name
+    index = this@toDomainEntity.name.substring(0, 1)
+}
+
+fun List<APIGenre>.toDomainEntityList(): List<Genre> = this.map { it.toDomainEntity() }

ultrasonic/src/test/kotlin/org/moire/ultrasonic/data/ApiGenreConverterTest.kt

@@ -0,0 +1,38 @@
+@file:Suppress("IllegalIdentifier")
+
+package org.moire.ultrasonic.data
+
+import org.amshove.kluent.`should equal to`
+import org.amshove.kluent.`should equal`
+import org.junit.Test
+import org.moire.ultrasonic.api.subsonic.models.Genre
+
+/**
+ * Unit test for for converter from api [Genre] to domain entity.
+ */
+class ApiGenreConverterTest {
+    @Test
+    fun `Should convert to domain entity`() {
+        val entity = Genre(songCount = 220, albumCount = 123, name = "some-name")
+
+        val domainEntity = entity.toDomainEntity()
+
+        with(domainEntity) {
+            name `should equal to` entity.name
+            index `should equal to` "s"
+        }
+    }
+
+    @Test
+    fun `Should convert a list entites to domain entities`() {
+        val entitiesList = listOf(
+                Genre(41, 2, "some-name"),
+                Genre(12, 3, "other-name"))
+
+        val domainEntitiesList = entitiesList.toDomainEntityList()
+
+        domainEntitiesList.size `should equal to` entitiesList.size
+        domainEntitiesList[0] `should equal` entitiesList[0].toDomainEntity()
+        domainEntitiesList[1] `should equal` entitiesList[1].toDomainEntity()
+    }
+}