Fix negative fine pitch across octave boundaries

pom.xml

@@ -39,6 +39,12 @@
 			<version>3.0.0</version>
 			<scope>compile</scope>
 		</dependency>
+		<dependency>
+			<groupId>junit</groupId>
+			<artifactId>junit</artifactId>
+			<version>4.13.2</version>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/com/xxmicloxx/NoteBlockAPI/utils/NoteUtils.java

@@ -44,7 +44,7 @@ public static float getPitchInOctave(Note note) {
     public static float getPitchInOctave(byte key, short pitch) {
         // Apply pitch to key
         key = applyPitchToKey(key, pitch);
-        pitch %= 100;
+        pitch = (short) Math.floorMod(pitch, 100);
 
         // -15 base_-2
         // 9 base_-1
@@ -62,7 +62,7 @@ public static float getPitchInOctave(byte key, short pitch) {
     }
 
     public static byte applyPitchToKey(byte key, short pitch) {
-        key += pitch / 100;
+        key += Math.floorDiv(pitch, 100);
         return key;
     }
 

src/test/java/com/xxmicloxx/NoteBlockAPI/utils/NoteUtilsTest.java

@@ -0,0 +1,24 @@
+package com.xxmicloxx.NoteBlockAPI.utils;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class NoteUtilsTest {
+
+	@Test
+	public void negativeFinePitchMovesToPreviousKeyWithoutIndexUnderflow() {
+		assertEquals(32, NoteUtils.applyPitchToKey((byte) 33, (short) -30));
+		assertEquals(expectedPitch(2370), NoteUtils.getPitchInOctave((byte) 33, (short) -30), 0.000001f);
+	}
+
+	@Test
+	public void negativeFinePitchSelectsThePreviousOctaveSample() {
+		assertEquals("test_-1", InstrumentUtils.warpNameOutOfRange("test", (byte) 33, (short) -30));
+		assertEquals("test", InstrumentUtils.warpNameOutOfRange("test", (byte) 57, (short) -30));
+	}
+
+	private float expectedPitch(int index) {
+		return (float) Math.pow(2, (index - 1200d) / 1200d);
+	}
+}