From b682432ca01fa5bfb8b41818329a2b65c5ed12d0 Mon Sep 17 00:00:00 2001
From: boc-the-git <3479092+boc-the-git@users.noreply.github.com>
Date: Tue, 12 Nov 2019 15:39:42 +1100
Subject: [PATCH] Change roundTo method to use BigDecimal rather than Double
 for more accurate comparison. Update tests to introduce more scenarios where
 without the code change, they'd fail.

---
 .../info/nightscout/androidaps/utils/Round.java   | 15 ++++++++++++---
 .../nightscout/androidaps/utils/RoundTest.java    | 13 ++++++++++---
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/app/src/main/java/info/nightscout/androidaps/utils/Round.java b/app/src/main/java/info/nightscout/androidaps/utils/Round.java
index ba7f7e3f86..3e312a20a9 100644
--- a/app/src/main/java/info/nightscout/androidaps/utils/Round.java
+++ b/app/src/main/java/info/nightscout/androidaps/utils/Round.java
@@ -1,14 +1,23 @@
 package info.nightscout.androidaps.utils;
 
+import java.math.BigDecimal;
+
 /**
  * Created by mike on 20.06.2016.
  */
 public class Round {
     public static Double roundTo(double x, Double step) {
-        if (x != 0d) {
-            return Math.round(x / step) * step;
+        if (x == 0d) {
+            return 0d;
         }
-        return 0d;
+
+        //Double oldCalc = Math.round(x / step) * step;
+        Double newCalc = BigDecimal.valueOf(Math.round(x / step)).multiply(BigDecimal.valueOf(step)).doubleValue();
+
+        // just for the tests, forcing failures
+        //newCalc = oldCalc;
+
+        return newCalc;
     }
     public static Double floorTo(Double x, Double step) {
         if (x != 0d) {
diff --git a/app/src/test/java/info/nightscout/androidaps/utils/RoundTest.java b/app/src/test/java/info/nightscout/androidaps/utils/RoundTest.java
index fb444804bc..568b67057e 100644
--- a/app/src/test/java/info/nightscout/androidaps/utils/RoundTest.java
+++ b/app/src/test/java/info/nightscout/androidaps/utils/RoundTest.java
@@ -12,9 +12,16 @@ public class RoundTest {
 
     @Test
     public void roundToTest() throws Exception {
-        assertEquals( 0.55d, Round.roundTo(0.54d, 0.05d), 0.00000001d );
-        assertEquals( 1d, Round.roundTo(1.49d, 1d), 0.00000001d );
-        assertEquals( 0d, Round.roundTo(0d, 1d), 0.00000001d );
+        assertEquals( 0.55d, Round.roundTo(0.54d, 0.05d), 0.00000000000000000001d );
+        assertEquals( -3.26d, Round.roundTo(-3.2553715764602713d, 0.01d), 0.00000000000000000001d );
+        assertEquals( 0.816d, Round.roundTo(0.8156666666666667d, 0.001d), 0.00000000000000000001d );
+        assertEquals( 0.235d, Round.roundTo(0.235d, 0.001d), 0.00000000000000000001d );
+        assertEquals( 0.3d, Round.roundTo(0.3d, 0.1d), 0.00000000000000001d );
+        assertEquals( 0.0017d, Round.roundTo(0.0016960652144170627d, 0.0001d), 0.00000000000000000001d );
+        assertEquals( 0.0078d, Round.roundTo(0.007804436682291013d, 0.0001d), 0.00000000000000000001d );
+        assertEquals( 0.6d, Round.roundTo(0.6d, 0.05d), 0.00000000000000000001d );
+        assertEquals( 1d, Round.roundTo(1.49d, 1d), 0.00000000000000000001d );
+        assertEquals( 0d, Round.roundTo(0d, 1d), 0.00000000000000000001d );
     }
 
     @Test