add tests for unit ConvertUtils.

Author: johnnzhou

app/src/main/java/com/lcl/lclmeasurementtool/Utils/ConvertUtils.java

@@ -1,43 +1,25 @@
 package com.lcl.lclmeasurementtool.Utils;
 
+/**
+ * Utilities that will be used to convert units.
+ */
 public class ConvertUtils {
 
     /**
-     * the conversion rate between megabit and megabyte.
-     */
-    public static final int CONVERSION_RATE = 8;
-
-    /**
-     * Convert data in MBps to Mbps.
-     *
-     * @param MBps the data to be converted in MBps.
-     * @throws IllegalArgumentException if MBps is less than 0.
-     * @return corresponding data in Mbps.
-     */
-    public static double toMbps(double MBps) {
-        if (MBps < 0) {
-            throw new IllegalArgumentException("the input parameter MBps should be greater than 0");
-        }
-        return MBps * CONVERSION_RATE;
-    }
-
-    /**
-     * Convert data in Mbps to MBps.
+     * Convert data from one unit to the other.
      *
-     * @param Mbps the data to be converted in Mbps.
-     * @throws IllegalArgumentException if Mbps is less than 0.
-     * @return corresponding data in MBps.
+     * @param from the base unit to be converted from.
+     * @param to   the destination unit to be converted to.
+     * @param data the data whose unit will be converted.
+     * @throws IllegalArgumentException if input data is less than 0.
+     * @return a double in the the destination unit.
      */
-    public static double toMBps(double Mbps) {
-        if (Mbps < 0) {
-            throw new IllegalArgumentException("the input parameter Mbps should be greater than 0");
-        }
-        return Mbps / CONVERSION_RATE;
-    }
-
     public static double convert(DataTransferRateUnit from,
                                  DataTransferRateUnit to,
                                  double data) {
+        if (data < 0) {
+            throw new IllegalArgumentException("the input parameter Mbps should be greater than 0");
+        }
 
         double unitConversionRate = 1.0;
         if (!from.getUnit().equals(to.getUnit())) {
@@ -53,6 +35,5 @@ public static double convert(DataTransferRateUnit from,
         }
 
         return data * unitConversionRate * magnitudeConversionRate;
-
     }
 }

app/src/test/java/com/lcl/lclmeasurementtool/ConvertUtilUnitTest.java

@@ -16,29 +16,33 @@
 public class ConvertUtilUnitTest {
     @Test
     public void testUnitConversion() {
-        assertEquals(
-                ConvertUtils.convert(DataTransferRateUnit.Kilobit, DataTransferRateUnit.Kilobyte, 1000),
-                125, 0.1
-        );
-
-        assertEquals(
-                ConvertUtils.convert(DataTransferRateUnit.Kilobit, DataTransferRateUnit.Megabit, 1000),
-                1, 0.1
-        );
-
-        assertEquals(
-                ConvertUtils.convert(DataTransferRateUnit.Kilobit, DataTransferRateUnit.Megabit, 1000),
-                1, 0.1
-        );
+        double data = 100.0;
+        double[] actual = new double[] {
+                100, 12.5, 0.1, 0.0125, 0.0001, 0.0000125,          // kb to all other
+                800, 100, 0.8, 0.1, 0.0008, 0.0001,                 // kB to all other
+                100000, 12500, 100, 12.5, 0.1, 0.0125,              // mb to all other
+                800000, 100000, 800, 100, 0.8, 0.1,                 // mB to all other
+                100000000, 12500000, 100000, 12500, 100, 12.5,      // gb to all other
+                800000000, 100000000, 800000, 100000, 800, 100      // gB to all other
+        };
 
         List<List<DataTransferRateUnit>> res = findAllCombination();
 
-        for (List<DataTransferRateUnit> list : res) {
-            System.out.println(list);
+        for (int i = 0; i < res.size(); i++) {
+            List<DataTransferRateUnit> list = res.get(i);
+            assertEquals(
+                    ConvertUtils.convert(list.get(0), list.get(1), data),  actual[i], 0.001
+            );
         }
+    }
 
+    @Test(expected = IllegalArgumentException.class)
+    public void testInvalidData() {
+        ConvertUtils.convert(DataTransferRateUnit.Kilobit, DataTransferRateUnit.Megabit, -100);
     }
 
+    // TODO: should also include tests for very large/small numbers
+
     private List<List<DataTransferRateUnit>> findAllCombination() {
         List<List<DataTransferRateUnit>> res = new ArrayList<>();
         find(0, DataTransferRateUnit.values(), new ArrayList<>(), res);