mock web failures

src/CalcViewModel/DataLoaders/CurrencyHttpClient.cpp

@@ -127,6 +127,7 @@ namespace
 
 namespace CalculatorApp::ViewModel::DataLoaders
 {
+    bool CurrencyHttpClient::ForceWebFailure = false;
     void CurrencyHttpClient::Initialize(Platform::String ^ sourceCurrencyCode, Platform::String ^ responseLanguage)
     {
         m_sourceCurrencyCode = sourceCurrencyCode;

src/CalcViewModel/DataLoaders/CurrencyHttpClient.h

@@ -8,6 +8,7 @@ namespace CalculatorApp::ViewModel::DataLoaders
     class CurrencyHttpClient
     {
     public:
+        static bool ForceWebFailure;
         void Initialize(Platform::String ^ sourceCurrencyCode, Platform::String ^ responseLanguage);
 
         Platform::String ^ GetCurrencyMetadata() const;

src/CalcViewModelCopyForUT/CalcViewModelCopyForUT.vcxproj

@@ -319,7 +319,6 @@
     <ClInclude Include="..\CalcViewModel\Common\TraceLogger.h" />
     <ClInclude Include="..\CalcViewModel\Common\Utils.h" />
     <ClInclude Include="..\CalcViewModel\DataLoaders\CurrencyDataLoader.h" />
-    <ClInclude Include="..\CalcViewModel\DataLoaders\CurrencyHttpClient.h" />
     <ClInclude Include="..\CalcViewModel\DataLoaders\UnitConverterDataConstants.h" />
     <ClInclude Include="..\CalcViewModel\DataLoaders\UnitConverterDataLoader.h" />
     <ClInclude Include="..\CalcViewModel\DateCalculatorViewModel.h" />
@@ -377,7 +376,7 @@
     <ClCompile Include="..\CalcViewModel\Snapshots.cpp" />
     <ClCompile Include="..\CalcViewModel\StandardCalculatorViewModel.cpp" />
     <ClCompile Include="..\CalcViewModel\UnitConverterViewModel.cpp" />
-    <ClCompile Include="CurrencyHttpClient.cpp" />
+    <ClCompile Include="DataLoaders\CurrencyHttpClient.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\CalcManager\CalcManager.vcxproj">

src/CalcViewModelCopyForUT/DataLoaders/CurrencyHttpClient.cpp

@@ -2,7 +2,7 @@
 // Licensed under the MIT License.
 
 #include "pch.h"
-#include "CalcViewModel/DataLoaders/CurrencyHttpClient.h"
+#include "DataLoaders/CurrencyHttpClient.h"
 
 namespace
 {
@@ -14,6 +14,7 @@ namespace
 
 namespace CalculatorApp::ViewModel::DataLoaders
 {
+    bool CurrencyHttpClient::ForceWebFailure = false;
     void CurrencyHttpClient::Initialize(Platform::String ^ sourceCurrencyCode, Platform::String ^ responseLanguage)
     {
         m_sourceCurrencyCode = sourceCurrencyCode;
@@ -22,12 +23,20 @@ namespace CalculatorApp::ViewModel::DataLoaders
 
     Platform::String ^ CurrencyHttpClient::GetCurrencyMetadata() const
     {
+        if (ForceWebFailure)
+        {
+            throw ref new Platform::Exception(E_FAIL, L"Mocked Network Failure: failed to load currency metadata");
+        }
         (void)m_responseLanguage; // to be used in production.
         return ref new Platform::String(MockCurrencyStaticData);
     }
 
     Platform::String ^ CurrencyHttpClient::GetCurrencyRatios() const
     {
+        if (ForceWebFailure)
+        {
+            throw ref new Platform::Exception(E_FAIL, L"Mocked Network Failure: failed to load currency metadata");
+        }
         (void)m_sourceCurrencyCode; // to be used in production.
         return ref new Platform::String(MockCurrencyConverterData);
     }

src/CalculatorUnitTests/CurrencyConverterUnitTests.cpp

@@ -52,6 +52,27 @@ private:
 
 namespace CalculatorUnitTests
 {
+    namespace
+    {
+        template <class F>
+        auto ScopeGuard(F&& f)
+        {
+            struct ScopeExit
+            {
+                explicit ScopeExit(F&& ef)
+                    : ExitFunctor(std::forward<F>(ef))
+                {
+                }
+                ~ScopeExit()
+                {
+                    ExitFunctor();
+                }
+                F ExitFunctor;
+            };
+            return ScopeExit{ std::forward<F>(f) };
+        }
+    }
+
     constexpr auto sc_Language_EN = L"en-US";
 
     String^ SerializeContent(const std::vector<String^>& data)
@@ -165,6 +186,8 @@ TEST_METHOD(LoadFromCache_Fail_OlderThanADay)
     dayOld.UniversalTime = now.UniversalTime - CurrencyDataLoaderConstants::DayDuration - 1;
     InsertToLocalSettings(CurrencyDataLoaderConstants::CacheTimestampKey, dayOld);
 
+    auto guard = ScopeGuard([] { CurrencyHttpClient::ForceWebFailure = false; });
+    CurrencyHttpClient::ForceWebFailure = true;
     CurrencyDataLoader loader{ L"en-US" };
 
     bool didLoad = loader.TryLoadDataFromCacheAsync().get();
@@ -245,19 +268,10 @@ TEST_METHOD(LoadFromCache_Success)
     VERIFY_IS_TRUE(loader.LoadedFromCache());
 }
 
-TEST_METHOD(LoadFromWeb_Fail_ClientIsNullptr)
-{
-    CurrencyDataLoader loader{ L"en-US" };
-
-    bool didLoad = loader.TryLoadDataFromWebAsync().get();
-
-    VERIFY_IS_FALSE(didLoad);
-    VERIFY_IS_FALSE(loader.LoadFinished());
-    VERIFY_IS_FALSE(loader.LoadedFromWeb());
-}
-
 TEST_METHOD(LoadFromWeb_Fail_WebException)
 {
+    auto guard = ScopeGuard([] { CurrencyHttpClient::ForceWebFailure = false; });
+    CurrencyHttpClient::ForceWebFailure = true;
     CurrencyDataLoader loader{ L"en-US" };
 
     bool didLoad = loader.TryLoadDataFromWebAsync().get();