Merge remote-tracking branch 'upstream/master' into Fix245

src/CalcManager/CEngine/History.cpp

@@ -416,8 +416,11 @@ int CHistoryCollector::AddCommand(_In_ const std::shared_ptr<IExpressionCommand>
 // To Update the operands in the Expression according to the current Radix
 void CHistoryCollector::UpdateHistoryExpression(uint32_t radix, int32_t precision)
 {
-    if (m_spTokens != nullptr)
+    if (m_spTokens == nullptr)
     {
+        return;
+    }
+
     unsigned int size;
     IFT(m_spTokens->GetSize(&size));
 
@@ -444,7 +447,6 @@ void CHistoryCollector::UpdateHistoryExpression(uint32_t radix, int32_t precisio
     }
     SetExpressionDisplay();
 }
-}
 
 void CHistoryCollector::SetDecimalSymbol(wchar_t decimalSymbol)
 {

src/CalcManager/CalculatorManager.cpp

@@ -490,8 +490,12 @@ namespace CalculationManager
     void CalculatorManager::MemorizeNumber()
     {
         m_savedCommands.push_back(MEMORY_COMMAND_TO_UNSIGNED_CHAR(MemoryCommand::MemorizeNumber));
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         m_currentCalculatorEngine->ProcessCommand(IDC_STORE);
 
         auto memoryObjectPtr = m_currentCalculatorEngine->PersistedMemObject();
@@ -506,7 +510,6 @@ namespace CalculationManager
         }
         this->SetMemorizedNumbersString();
     }
-    }
 
     /// <summary>
     /// Recall the memorized number.
@@ -516,12 +519,15 @@ namespace CalculationManager
     void CalculatorManager::MemorizedNumberLoad(_In_ unsigned int indexOfMemory)
     {
         SaveMemoryCommand(MemoryCommand::MemorizedNumberLoad, indexOfMemory);
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         this->MemorizedNumberSelect(indexOfMemory);
         m_currentCalculatorEngine->ProcessCommand(IDC_RECALL);
     }
-    }
 
     /// <summary>
     /// Do the addition to the selected memory
@@ -532,8 +538,12 @@ namespace CalculationManager
     void CalculatorManager::MemorizedNumberAdd(_In_ unsigned int indexOfMemory)
     {
         SaveMemoryCommand(MemoryCommand::MemorizedNumberAdd, indexOfMemory);
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         if (m_memorizedNumbers.empty())
         {
             this->MemorizeNumber();
@@ -550,7 +560,6 @@ namespace CalculationManager
 
         m_displayCallback->MemoryItemChanged(indexOfMemory);
     }
-    }
 
     void CalculatorManager::MemorizedNumberClear(_In_ unsigned int indexOfMemory)
     {
@@ -570,8 +579,12 @@ namespace CalculationManager
     void CalculatorManager::MemorizedNumberSubtract(_In_ unsigned int indexOfMemory)
     {
         SaveMemoryCommand(MemoryCommand::MemorizedNumberSubtract, indexOfMemory);
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         // To add negative of the number on display to the memory -x = x - 2x
         if (m_memorizedNumbers.empty())
         {
@@ -591,7 +604,6 @@ namespace CalculationManager
 
         m_displayCallback->MemoryItemChanged(indexOfMemory);
     }
-    }
 
     /// <summary>
     /// Clear all the memorized values
@@ -613,12 +625,14 @@ namespace CalculationManager
 /// <param name="indexOfMemory">Index of the target memory</param>
     void CalculatorManager::MemorizedNumberSelect(_In_ unsigned int indexOfMemory)
     {
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         auto memoryObject = m_memorizedNumbers.at(indexOfMemory);
         m_currentCalculatorEngine->PersistedMemObject(memoryObject);
     }
-    }
 
     /// <summary>
     /// Helper function that needs to be executed when memory is modified
@@ -627,15 +641,17 @@ namespace CalculationManager
     /// <param name="indexOfMemory">Index of the target memory</param>
     void CalculatorManager::MemorizedNumberChanged(_In_ unsigned int indexOfMemory)
     {
-        if (!(m_currentCalculatorEngine->FInErrorState()))
+        if (m_currentCalculatorEngine->FInErrorState())
         {
+            return;
+        }
+
         auto memoryObject = m_currentCalculatorEngine->PersistedMemObject();
         if (memoryObject != nullptr)
         {
             m_memorizedNumbers.at(indexOfMemory) = *memoryObject;
         }
     }
-    }
 
     void CalculatorManager::SaveMemoryCommand(_In_ MemoryCommand command, _In_ unsigned int indexOfMemory)
     {

src/CalcManager/Ratpack/conv.cpp

@@ -612,6 +612,7 @@ PNUMBER StringToNumber(wstring_view numberString, uint32_t radix, int32_t precis
                 break;
             }
             // Drop through in the 'e'-as-a-digit case
+            [[fallthrough]];
         default:
             state = machine[state][NZ];
             break;
@@ -646,7 +647,7 @@ PNUMBER StringToNumber(wstring_view numberString, uint32_t radix, int32_t precis
             break;
         case LD:
             pnumret->exp++;
-            // Fall through
+            [[fallthrough]];
         case DD:
             {
                 curChar = NormalizeCharDigit(curChar, radix);

src/CalcManager/UnitConverter.cpp

@@ -109,22 +109,8 @@ CategorySelectionInitializer UnitConverter::SetCurrentCategory(const Category& i
             vector<Unit>& unitVector = m_categoryToUnits[m_currentCategory];
             for (unsigned int i = 0; i < unitVector.size(); i++)
             {
-                if (unitVector[i].id == m_fromType.id)
+                unitVector[i].isConversionSource = (unitVector[i].id == m_fromType.id);
-                {
+                unitVector[i].isConversionTarget = (unitVector[i].id == m_toType.id);
-                    unitVector[i].isConversionSource = true;
-                }
-                else
-                {
-                    unitVector[i].isConversionSource = false;
-                }
-                if (unitVector[i].id == m_toType.id)
-                {
-                    unitVector[i].isConversionTarget = true;
-                }
-                else
-                {
-                    unitVector[i].isConversionTarget = false;
-                }
             }
             m_currentCategory = input;
             if (!m_currentCategory.supportsNegative && m_currentDisplay.front() == L'-')
@@ -156,8 +142,11 @@ Category UnitConverter::GetCurrentCategory()
 /// <param name="toType">Unit struct we are converting to</param>
 void UnitConverter::SetCurrentUnitTypes(const Unit& fromType, const Unit& toType)
 {
-    if (CheckLoad())
+    if (!CheckLoad())
     {
+        return;
+    }
+
     m_fromType = fromType;
     m_toType = toType;
     Calculate();
@@ -165,7 +154,6 @@ void UnitConverter::SetCurrentUnitTypes(const Unit& fromType, const Unit& toType
     UpdateCurrencySymbols();
     UpdateViewModel();
 }
-}
 
 /// <summary>
 /// Switches the active field, indicating that we are now entering data into
@@ -181,8 +169,11 @@ void UnitConverter::SetCurrentUnitTypes(const Unit& fromType, const Unit& toType
 /// </param>
 void UnitConverter::SwitchActive(const wstring& newValue)
 {
-    if (CheckLoad())
+    if (!CheckLoad())
     {
+        return;
+    }
+
     swap(m_fromType, m_toType);
     swap(m_currentHasDecimal, m_returnHasDecimal);
     m_returnDisplay = m_currentDisplay;
@@ -198,7 +189,6 @@ void UnitConverter::SwitchActive(const wstring& newValue)
         m_vmCurrencyCallback->CurrencyRatiosCallback(currencyRatios.first, currencyRatios.second);
     }
 }
-}
 
 wstring UnitConverter::CategoryToString(const Category& c, const wchar_t * delimiter)
 {
@@ -291,8 +281,11 @@ wstring UnitConverter::ConversionDataToString(ConversionData d, const wchar_t *
 /// </summary>
 wstring UnitConverter::Serialize()
 {
-    if (CheckLoad())
+    if (!CheckLoad())
     {
+        return wstring();
+    }
+
     wstringstream out(wstringstream::out);
     const wchar_t * delimiter = L";";
 
@@ -336,11 +329,6 @@ wstring UnitConverter::Serialize()
     wstring test = out.str();
     return test;
 }
-    else
-    {
-        return wstring();
-    }
-}
 
 /// <summary>
 /// De-Serializes the data in the converter from a string
@@ -349,8 +337,12 @@ wstring UnitConverter::Serialize()
 void UnitConverter::DeSerialize(const wstring& serializedData)
 {
     Reset();
-    if (!serializedData.empty())
+
+    if (serializedData.empty())
     {
+        return;
+    }
+
     vector<wstring> outerTokens = StringToVector(serializedData, L"|");
     assert(outerTokens.size() == EXPECTEDSERIALIZEDTOKENCOUNT);
     m_fromType = StringToUnit(outerTokens[0]);
@@ -398,7 +390,6 @@ void UnitConverter::DeSerialize(const wstring& serializedData)
     }
     UpdateViewModel();
 }
-}
 
 /// <summary>
 /// De-Serializes the data in the converter from a string
@@ -406,8 +397,11 @@ void UnitConverter::DeSerialize(const wstring& serializedData)
 /// <param name="userPreferences">wstring holding the serialized data. If it does not have expected number of parameters, we will ignore it</param>
 void UnitConverter::RestoreUserPreferences(const wstring& userPreferences)
 {
-    if (!userPreferences.empty())
+    if (userPreferences.empty())
     {
+        return;
+    }
+
     vector<wstring> outerTokens = StringToVector(userPreferences, L"|");
     if (outerTokens.size() == 3)
     {
@@ -416,7 +410,6 @@ void UnitConverter::RestoreUserPreferences(const wstring& userPreferences)
         m_currentCategory = StringToCategory(outerTokens[2]);
     }
 }
-}
 
 /// <summary>
 /// Serializes the Category and Associated Units in the converter and returns it as a string
@@ -503,8 +496,11 @@ wstring UnitConverter::Unquote(const wstring& s)
 /// <param name="command">Command enum representing the command that was entered</param>
 void UnitConverter::SendCommand(Command command)
 {
-    if (CheckLoad())
+    if (!CheckLoad())
     {
+        return;
+    }
+
     // TODO: Localization of characters
     bool clearFront = false;
     if (m_currentDisplay == L"0")
@@ -641,7 +637,6 @@ void UnitConverter::SendCommand(Command command)
 
     UpdateViewModel();
 }
-}
 
 /// <summary>
 /// Sets the callback interface to send display update calls to
@@ -844,8 +839,11 @@ void UnitConverter::Reset()
     ClearValues();
     m_switchedActive = false;
 
-    if (!m_categories.empty())
+    if (m_categories.empty())
     {
+        return;
+    }
+
     m_currentCategory = m_categories[0];
 
     m_categoryToUnits.clear();
@@ -885,7 +883,6 @@ void UnitConverter::Reset()
     InitializeSelectedUnits();
     Calculate();
 }
-}
 
 /// <summary>
 /// Sets the active data loader based on the input category.
@@ -1029,8 +1026,11 @@ void UnitConverter::Calculate()
 /// <param name="input">wstring to trim</param>
 void UnitConverter::TrimString(wstring& returnString)
 {
-    if (returnString.find(L'.') != m_returnDisplay.npos)
+    if (returnString.find(L'.') == m_returnDisplay.npos)
     {
+        return;
+    }
+
     wstring::iterator iter;
     for (iter = returnString.end() - 1; ;iter--)
     {
@@ -1045,7 +1045,6 @@ void UnitConverter::TrimString(wstring& returnString)
         returnString.erase(returnString.end()-1, returnString.end());
     }
 }
-}
 
 /// <summary>
 /// Rounds the given double to the given number of significant digits

src/CalcViewModel/Common/DateCalculator.cpp

@@ -12,6 +12,7 @@ using namespace CalculatorApp::Common::DateCalculation;
 DateCalculationEngine::DateCalculationEngine(_In_ String^ calendarIdentifier)
 {
     m_calendar = ref new Calendar();
+    m_calendar->ChangeTimeZone("UTC");
     m_calendar->ChangeCalendarSystem(calendarIdentifier);
 }
 

src/CalcViewModel/DateCalculatorViewModel.cpp

@@ -43,11 +43,7 @@ DateCalculatorViewModel::DateCalculatorViewModel() :
     m_StrDateDiffResultAutomationName(L""),
     m_StrDateDiffResultInDays(L""),
     m_StrDateResult(L""),
-    m_StrDateResultAutomationName(L""),
+    m_StrDateResultAutomationName(L"")
-    m_fromDate({ 0 }),
-    m_toDate({ 0 }),
-    m_startDate({ 0 }),
-    m_dateResult({ 0 })
 {
     const auto& localizationSettings = LocalizationSettings::GetInstance();
 
@@ -56,19 +52,19 @@ DateCalculatorViewModel::DateCalculatorViewModel() :
 
     // Initialize Date Calc engine
     m_dateCalcEngine = make_shared<DateCalculationEngine>(localizationSettings.GetCalendarIdentifier());
-
     // Initialize dates of DatePicker controls to today's date
     auto calendar = ref new Calendar();
+    // We force the timezone to UTC, in order to avoid being affected by Daylight Saving Time
+    // when we calculate the difference between 2 dates. 
+    calendar->ChangeTimeZone("UTC");
     auto today = calendar->GetDateTime();
 
     // FromDate and ToDate should be clipped (adjusted to a consistent hour in UTC)
-    m_fromDate = today;
+    m_fromDate = ClipTime(today);
-    m_toDate = today;
+    m_toDate = ClipTime(today);
-    FromDate = ClipTime(today);
-    ToDate = ClipTime(today);
 
     // StartDate should not be clipped
-    StartDate = today;
+    m_startDate = today;
     m_dateResult = today;
 
     // Initialize the list separator delimiter appended with a space at the end, e.g. ", "
@@ -86,15 +82,6 @@ DateCalculatorViewModel::DateCalculatorViewModel() :
         m_offsetValues->Append(ref new String(numberStr.c_str()));
     }
 
-    /* In the ClipTime function, we used to change timezone to UTC before clipping the time.
-       The comment from the previous developers said this was done to eliminate the effects of
-       Daylight Savings Time. We can't think of a good reason why this change in timezone is
-       necessary and did find bugs related to the change, therefore, we have removed the
-       change. Just in case, we will see if the clipped time is ever a different day from the
-       original day, which would hopefully indicate the change in timezone was actually
-       necessary. We will collect telemetry if we find this case. If we don't see any
-       telemetry events after the application has been used for some time, we will feel safe
-       and can remove this function. */
     DayOfWeek trueDayOfWeek = calendar->DayOfWeek;
 
     DateTime clippedTime = ClipTime(today);
@@ -383,13 +370,14 @@ String^ DateCalculatorViewModel::GetLocalizedNumberString(int value) const
     return ref new String(numberStr.c_str());
 }
 
-// Adjusts the given DateTime to 12AM of the same day
+// Adjusts the given DateTime to 12AM (UTC) of the same day
 DateTime DateCalculatorViewModel::ClipTime(DateTime dateTime)
 {
     auto calendar = ref new Calendar();
+    calendar->ChangeTimeZone("UTC");
     calendar->SetDateTime(dateTime);
-    calendar->Period = 1;
+    calendar->Period = calendar->FirstPeriodInThisDay;
-    calendar->Hour = 12;
+    calendar->Hour = calendar->FirstHourInThisPeriod;
     calendar->Minute = 0;
     calendar->Second = 0;
     calendar->Nanosecond = 0;

src/CalcViewModel/DateCalculatorViewModel.h

@@ -23,7 +23,7 @@ namespace CalculatorApp
             // Input Properties
             OBSERVABLE_PROPERTY_RW(bool, IsDateDiffMode);
             OBSERVABLE_PROPERTY_RW(bool, IsAddMode);
-            OBSERVABLE_PROPERTY_RW(bool, IsDiffInDays);     // If diff is only in days or the dates are the same,
+            OBSERVABLE_PROPERTY_R(bool, IsDiffInDays);     // If diff is only in days or the dates are the same,
                                                            // then show only one result and avoid redundancy
 
             OBSERVABLE_PROPERTY_RW(int, DaysOffset);
@@ -82,11 +82,11 @@ namespace CalculatorApp
             }
 
             // Output Properties
-            OBSERVABLE_PROPERTY_RW(Platform::String^, StrDateDiffResult);
+            OBSERVABLE_PROPERTY_R(Platform::String^, StrDateDiffResult);
-            OBSERVABLE_PROPERTY_RW(Platform::String^, StrDateDiffResultAutomationName);
+            OBSERVABLE_PROPERTY_R(Platform::String^, StrDateDiffResultAutomationName);
-            OBSERVABLE_PROPERTY_RW(Platform::String^, StrDateDiffResultInDays);
+            OBSERVABLE_PROPERTY_R(Platform::String^, StrDateDiffResultInDays);
-            OBSERVABLE_PROPERTY_RW(Platform::String^, StrDateResult);
+            OBSERVABLE_PROPERTY_R(Platform::String^, StrDateResult);
-            OBSERVABLE_PROPERTY_RW(Platform::String^, StrDateResultAutomationName);
+            OBSERVABLE_PROPERTY_R(Platform::String^, StrDateResultAutomationName);
 
             COMMAND_FOR_METHOD(CopyCommand, DateCalculatorViewModel::OnCopyCommand);
 
@@ -104,8 +104,6 @@ namespace CalculatorApp
             Platform::String^ GetLocalizedNumberString(int value) const;
             static Windows::Foundation::DateTime ClipTime(Windows::Foundation::DateTime dateTime);
 
-            static void CheckClipTimeSameDay(Windows::Globalization::Calendar^ reference);
-
             property bool IsOutOfBound
             {
                 bool get() { return m_isOutOfBound; }

src/CalcViewModel/UnitConverterViewModel.cpp

@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft Corporation. All rights reserved.
+// Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
 #include "pch.h"
@@ -53,6 +53,8 @@ constexpr size_t SELECTED_TARGET_UNIT = 2;
 
 // x millisecond delay before we consider conversion to be final
 constexpr unsigned int CONVERSION_FINALIZED_DELAY_IN_MS = 1000;
+const wregex regexTrimSpacesStart = wregex(L"^\\s+");
+const wregex regexTrimSpacesEnd = wregex(L"\\s+$");
 
 namespace CalculatorApp::ViewModel
 {
@@ -202,13 +204,11 @@ void UnitConverterViewModel::BuildUnitList(const vector<UCM::Unit>& modelUnitLis
     m_Units->Clear();
     for (const UCM::Unit& modelUnit : modelUnitList)
     {
-        if (modelUnit.isWhimsical)
+        if (!modelUnit.isWhimsical)
         {
-            continue;
-        }
-
             m_Units->Append(ref new Unit(modelUnit));
         }
+    }
 
     if (m_Units->Size == 0)
     {
@@ -348,10 +348,15 @@ String^ UnitConverterViewModel::ConvertToLocalizedString(const std::wstring& str
             if (pos != wstring::npos)
             {
                 currencyResult.erase(pos, currencyCode.length());
-                pos = currencyResult.find(L'\u00a0'); // non-breaking space
+                std::wsmatch sm;
-                if (pos != wstring::npos)
+                if (regex_search(currencyResult, sm, regexTrimSpacesStart))
                 {
-                    currencyResult.erase(pos, 1);
+                    currencyResult.erase(sm.prefix().length(), sm.length());
+                }
+
+                if (regex_search(currencyResult, sm, regexTrimSpacesEnd))
+                {
+                    currencyResult.erase(sm.prefix().length(), sm.length());
                 }
             }
 
@@ -643,11 +648,9 @@ String^ UnitConverterViewModel::Serialize()
         String^ serializedData = ref new String(wstring(out.str()).c_str());
         return serializedData;
     }
-    else
+
-    {
     return nullptr;
 }
-}
 
 void UnitConverterViewModel::Deserialize(Platform::String^ state)
 {
@@ -879,14 +882,11 @@ void UnitConverterViewModel::UpdateInputBlocked(_In_ const wstring& currencyInpu
 {
     // currencyInput is in en-US and has the default decimal separator, so this is safe to do.
     auto posOfDecimal = currencyInput.find(L'.');
+    m_isInputBlocked  = false;
     if (posOfDecimal != wstring::npos && IsCurrencyCurrentCategory)
     {
         m_isInputBlocked = (posOfDecimal + static_cast<size_t>(m_currencyMaxFractionDigits) + 1 == currencyInput.length());
     }
-    else
-    {
-        m_isInputBlocked = false;
-    }
 }
 
 NumbersAndOperatorsEnum UnitConverterViewModel::MapCharacterToButtonId(
@@ -988,7 +988,7 @@ void UnitConverterViewModel::OnPaste(String^ stringToPaste, ViewMode mode)
             }
 
             // Negate is only allowed if it's the first legal character, which is handled above.
-            if (NumbersAndOperatorsEnum::None != op && NumbersAndOperatorsEnum::Negate != op)
+            if (NumbersAndOperatorsEnum::Negate != op)
             {
                 UCM::Command cmd = CommandFromButtonId(op);
                 m_model->SendCommand(cmd);

src/Calculator/Views/Calculator.xaml

@@ -515,6 +515,7 @@
                         <Setter Target="M5.MaxWidth" Value="80"/>
                         <Setter Target="memButton.(Grid.Column)" Value="5"/>
                         <Setter Target="MemoryButton.(Grid.Column)" Value="6"/>
+                        <Setter Target="HistoryButton.Visibility" Value="Collapsed"/>
                     </VisualState.Setters>
                     <Storyboard Completed="OnStoryboardCompleted"/>
                 </VisualState>

src/Calculator/Views/Calculator.xaml.cpp

@@ -415,7 +415,7 @@ void Calculator::UpdateHistoryState()
         SetChildAsHistory();
         HistoryButton->Visibility = ::Visibility::Collapsed;
 
-        if (m_IsLastFlyoutHistory)
+        if (!IsProgrammer && m_IsLastFlyoutHistory)
         {
             DockPivot->SelectedIndex = 0;
         }
@@ -522,7 +522,7 @@ void Calculator::HistoryFlyout_Closed(_In_ Object ^sender, _In_ Object ^args)
     AutomationProperties::SetName(HistoryButton, m_openHistoryFlyoutAutomationName);
     m_fIsHistoryFlyoutOpen = false;
     EnableControls(true);
-    if (HistoryButton->IsEnabled)
+    if (HistoryButton->IsEnabled && HistoryButton->Visibility == ::Visibility::Visible)
     {
         HistoryButton->Focus(::FocusState::Programmatic);
     }

src/CalculatorUnitTests/DateCalculatorUnitTests.cpp

@@ -387,6 +387,63 @@ namespace DateCalculationUnitTests
             VERIFY_IS_TRUE(StringReference(L"") != viewModel->StrDateResult);
         }
 
+        TEST_METHOD(DateCalcViewModelDateDiffDaylightSavingTimeTest)
+        {
+          auto viewModel = ref new DateCalculatorViewModel();
+
+          viewModel->IsDateDiffMode = true;
+          VERIFY_IS_TRUE(viewModel->IsDateDiffMode);
+
+          // 29.02.2008
+          viewModel->FromDate = DateUtils::SystemTimeToDateTime(datetimeDifftest[5].startDate);
+          // 31.03.2008
+          viewModel->ToDate = DateUtils::SystemTimeToDateTime(datetimeDifftest[5].endDate);
+
+          //// Assert for the result
+          VERIFY_IS_FALSE(viewModel->IsDiffInDays);
+          VERIFY_ARE_EQUAL(StringReference(L"31 days"), viewModel->StrDateDiffResultInDays);
+          VERIFY_ARE_EQUAL(StringReference(L"1 month, 2 days"), viewModel->StrDateDiffResult);
+
+          // Daylight Saving Time - Clock Forward
+          // 10.03.2019
+          SYSTEMTIME startDate;
+          startDate.wYear = 2019;
+          startDate.wMonth = 03;
+          startDate.wDay = 10;
+          startDate.wDayOfWeek = 0;
+          startDate.wHour = startDate.wMinute = 0;
+          startDate.wSecond = startDate.wMilliseconds = 0;
+          viewModel->FromDate = DateUtils::SystemTimeToDateTime(startDate);
+          // 11.03.2019
+          SYSTEMTIME endDate;
+          endDate.wYear = 2019;
+          endDate.wMonth = 03;
+          endDate.wDay = 11;
+          endDate.wDayOfWeek = 0;
+          endDate.wHour = endDate.wMinute = 0;
+          endDate.wSecond = endDate.wMilliseconds = 0;
+          viewModel->ToDate = DateUtils::SystemTimeToDateTime(endDate);
+          VERIFY_IS_TRUE(viewModel->IsDiffInDays);
+          VERIFY_ARE_EQUAL(StringReference(L"1 day"), viewModel->StrDateDiffResult);
+
+          endDate.wDay += 6;
+          viewModel->ToDate = DateUtils::SystemTimeToDateTime(endDate);
+          VERIFY_IS_FALSE(viewModel->IsDiffInDays);
+          VERIFY_ARE_EQUAL(StringReference(L"1 week"), viewModel->StrDateDiffResult);
+
+          // Daylight Saving Time - Clock Backward
+          // 03.11.2019
+          startDate.wMonth = 11;
+          startDate.wDay = 03;
+          viewModel->FromDate = DateUtils::SystemTimeToDateTime(startDate);
+          // 04.11.2019
+          endDate.wMonth = 11;
+          endDate.wDay = 04;
+          viewModel->ToDate = DateUtils::SystemTimeToDateTime(endDate);
+          VERIFY_IS_TRUE(viewModel->IsDiffInDays);
+          VERIFY_ARE_EQUAL(StringReference(L"1 day"), viewModel->StrDateDiffResult);
+        }
+
         TEST_METHOD(DateCalcViewModelAddTest)
         {
             // TODO - MSFT 10331900, fix this test