diff --git a/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java b/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java
index 547bec8b4..0b47cc000 100644
--- a/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java
+++ b/uhabits-android/src/main/java/org/isoron/uhabits/activities/common/views/FrequencyChart.java
@@ -203,7 +203,7 @@ public class FrequencyChart extends ScrollableChart
             rect.set(0, 0, baseSize, baseSize);
             rect.offset(prevRect.left, prevRect.top + baseSize * j);
 
-            int i = DateUtils.javaWeekdayToLoopWeekday(localeWeekdayList[j]);
+            int i = localeWeekdayList[j] % 7;
             if (values != null) drawMarker(canvas, rect, values[i]);
 
             rect.offset(0, rowHeight);
diff --git a/uhabits-core/src/test/java/org/isoron/uhabits/core/models/CheckmarkListTest.java b/uhabits-core/src/test/java/org/isoron/uhabits/core/models/CheckmarkListTest.java
index b3b55034f..4de458c05 100644
--- a/uhabits-core/src/test/java/org/isoron/uhabits/core/models/CheckmarkListTest.java
+++ b/uhabits-core/src/test/java/org/isoron/uhabits/core/models/CheckmarkListTest.java
@@ -34,7 +34,7 @@ public class CheckmarkListTest extends BaseUnitTest
 {
     private long dayLength;
 
-    private long today;
+    private Timestamp today;
 
     private Habit nonDailyHabit;
 
@@ -55,6 +55,7 @@ public class CheckmarkListTest extends BaseUnitTest
 
         numericalHabit = fixtures.createNumericalHabit();
         habitList.add(numericalHabit);
+        today = DateUtils.getToday();
     }
 
     @Test
@@ -285,8 +286,8 @@ public class CheckmarkListTest extends BaseUnitTest
     @Test
     public void test_getValues_withValidInterval()
     {
-        long from = today - 15 * dayLength;
-        long to = today - 5 * dayLength;
+        Timestamp from = today.minus(15);
+        Timestamp to = today.minus(5);
 
         int[] expectedValues = {
             CHECKED_EXPLICITLY,
@@ -302,10 +303,7 @@ public class CheckmarkListTest extends BaseUnitTest
             UNCHECKED
         };
 
-        int[] actualValues = nonDailyHabit
-            .getCheckmarks()
-            .getValues(new Timestamp(from), new Timestamp(to));
-
+        int[] actualValues = nonDailyHabit.getCheckmarks().getValues(from, to);
         assertThat(actualValues, equalTo(expectedValues));
     }
 
diff --git a/uhabits-core/src/test/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.java b/uhabits-core/src/test/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.java
index 93d93b861..0ed3fbbab 100644
--- a/uhabits-core/src/test/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.java
+++ b/uhabits-core/src/test/java/org/isoron/uhabits/core/ui/screens/habits/list/ListHabitsBehaviorTest.java
@@ -152,7 +152,7 @@ public class ListHabitsBehaviorTest extends BaseUnitTest
     @Test
     public void testOnStartup_firstLaunch()
     {
-        long today = DateUtils.getStartOfToday();
+        Timestamp today = DateUtils.getToday();
 
         when(prefs.isFirstRun()).thenReturn(true);
         behavior.onStartup();
diff --git a/uhabits-core/src/test/java/org/isoron/uhabits/core/utils/DateUtilsTest.java b/uhabits-core/src/test/java/org/isoron/uhabits/core/utils/DateUtilsTest.java
index 11590260c..9af9c3981 100644
--- a/uhabits-core/src/test/java/org/isoron/uhabits/core/utils/DateUtilsTest.java
+++ b/uhabits-core/src/test/java/org/isoron/uhabits/core/utils/DateUtilsTest.java
@@ -20,6 +20,7 @@
 package org.isoron.uhabits.core.utils;
 
 import org.isoron.uhabits.core.*;
+import org.isoron.uhabits.core.models.*;
 import org.junit.*;
 
 import java.util.*;
@@ -34,7 +35,7 @@ public class DateUtilsTest extends BaseUnitTest
     public void testFormatHeaderDate()
     {
         long timestamp = timestamp(2015, DECEMBER, 31);
-        GregorianCalendar date = DateUtils.getCalendar(timestamp);
+        GregorianCalendar date = new Timestamp(timestamp).toCalendar();
         String formatted = DateUtils.formatHeaderDate(date);
         assertThat(formatted, equalTo("Thu\n31"));
     }