UtilTest: Added unit tests for Util.java

lib/src/test/java/org/fairportrobotics/frc/robolib/UtilTest.java

@@ -0,0 +1,31 @@
+package org.fairportrobotics.frc.robolib;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+public class UtilTest {
+    @Test void testRangePercent() {
+        assertEquals(
+            0.2,
+            Util.rangePercent(0, 10, 2),
+            "Positives, Normal"
+        );
+        assertEquals(
+            0.8,
+            Util.rangePercent(10, 0, 2),
+            "Positives, Reversed"
+        );
+        assertEquals(
+            0.8,
+            Util.rangePercent(-10, 0, -2),
+            "Negatives, Normal"
+        );
+        assertEquals(
+            0.2,
+            Util.rangePercent(0, -10, -2),
+            "Negatives, Reversed"
+        );
+
+    }
+}