(GH-79) Add specific exception message in GenericStrategyProvider (#80)

* .NET 6 * Added more specific exception message. Co-authored-by: Urs Muntwyler <urs.muntwyler@bbtsoftware.ch>
bbtsoftware · Jan 16, 2023 · 9ea4068 · 9ea4068
1 parent df23395
commit 9ea4068
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Showing 4 changed files with 66 additions and 29 deletions.
diff --git a/src/BBT.StrategyPattern.Tests/BBT.StrategyPattern.Tests.csproj b/src/BBT.StrategyPattern.Tests/BBT.StrategyPattern.Tests.csproj
@@ -33,10 +33,4 @@
     <ProjectReference Include="..\BBT.StrategyPattern\BBT.StrategyPattern.csproj" />
   </ItemGroup>
 
-  <ItemGroup>
-    <Reference Include="System">
-      <HintPath>System</HintPath>
-    </Reference>
-  </ItemGroup>
-
 </Project>
diff --git a/src/BBT.StrategyPattern.Tests/WithIocTest.cs b/src/BBT.StrategyPattern.Tests/WithIocTest.cs
@@ -2,6 +2,7 @@
 
 namespace BBT.StrategyPattern.Tests
 {
+    using System;
     using BBT.StrategyPattern.Tests.Data;
     using BBT.StrategyPattern.Tests.ExampleStrategyImpl;
     using BBT.StrategyPattern.Tests.WithIoc;
@@ -19,7 +20,6 @@ public void WorksWithIocNinject()
             var op1 = new Operator() { Operation = OperatorEnum.Addition };
             var op2 = new Operator() { Operation = OperatorEnum.Subtraktion };
 
-
             // IoC registrations
             IKernel kernel = new StandardKernel();
 
@@ -39,5 +39,55 @@ public void WorksWithIocNinject()
             strategy = kernel.Get<IGenericStrategyProvider<IOperatorStrategy, Operator>>().GetStrategy(op2);
             strategy.DoCalculate(calc1).Should().Be(2);
         }
+
+        [Fact]
+        public void MissingStrategies_ThrowsExpectedException()
+        {
+            // Prepare data
+            var calc1 = new CalculationInput() { Number1 = 5, Number2 = 3 };
+            var op1 = new Operator() { Operation = OperatorEnum.Addition };
+            var op2 = new Operator() { Operation = OperatorEnum.Subtraktion };
+
+            // IoC registrations (note: do not register any IOperatorStrategy strategy)
+            IKernel kernel = new StandardKernel();
+
+            kernel.Bind(typeof(IStrategyLocator<>)).To(typeof(NinjectStrategyLocator<>));
+            kernel.Bind<IGenericStrategyProvider<IOperatorStrategy, Operator>>().To<GenericStrategyProvider<IOperatorStrategy, Operator>>();
+
+            // Act
+            var act = () => kernel.Get<IGenericStrategyProvider<IOperatorStrategy, Operator>>().GetStrategy(op2);
+
+            // Assert
+            act.Should()
+                .Throw<InvalidOperationException>()
+                .WithMessage("No strategies of type IOperatorStrategy are available from the locator.");
+
+        }
+
+        [Fact]
+        public void MissingStrategyForCriteria_ThrowsExpectedException()
+        {
+            // Prepare data
+            var calc1 = new CalculationInput() { Number1 = 5, Number2 = 3 };
+            var op1 = new Operator() { Operation = OperatorEnum.Addition };
+            var op2 = new Operator() { Operation = OperatorEnum.Subtraktion };
+
+            // IoC registrations (note: do not register SubstractionStrategy)
+            IKernel kernel = new StandardKernel();
+
+            kernel.Bind(typeof(IStrategyLocator<>)).To(typeof(NinjectStrategyLocator<>));
+
+            kernel.Bind<IOperatorStrategy>().To<AdditionStrategy>();
+
+            kernel.Bind<IGenericStrategyProvider<IOperatorStrategy, Operator>>().To<GenericStrategyProvider<IOperatorStrategy, Operator>>();
+
+            // Act
+            var act = () => kernel.Get<IGenericStrategyProvider<IOperatorStrategy, Operator>>().GetStrategy(op2);
+
+            // Assert
+            act.Should()
+                .Throw<InvalidOperationException>()
+                .WithMessage("No strategy of type IOperatorStrategy available from the locator being responsible for criterion of type Operator.");
+        }
     }
-}
+}
diff --git a/src/BBT.StrategyPattern/BBT.StrategyPattern.csproj b/src/BBT.StrategyPattern/BBT.StrategyPattern.csproj
@@ -21,30 +21,11 @@
     <DebugType>pdbonly</DebugType>
   </PropertyGroup>
 
-  <!-- Workaround for malformed XML file in .NET Standard 2.0 (https://github.com/dotnet/standard/issues/1527) -->
-  <PropertyGroup Condition="'$(TargetFramework)'=='netstandard2.0'">
-	  <NoWarn>$(NoWarn);IDT001</NoWarn>
-  </PropertyGroup>
-  <ItemGroup Condition="'$(TargetFramework)'=='netstandard2.0'">
-    <PackageDownload Include="NETStandard.Library.Ref" Version="[2.1.0]" />
-    <InheritDocReference Include="$([MSBuild]::EnsureTrailingSlash('$(NugetPackageRoot)'))netstandard.library.ref\2.1.0\ref\netstandard2.1\netstandard.xml" />
-  </ItemGroup>
-
   <ItemGroup>
-    <PackageReference Include="coverlet.collector" Version="3.2.0">
-      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-      <PrivateAssets>all</PrivateAssets>
-    </PackageReference>
-    <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.3.2">
-      <PrivateAssets>all</PrivateAssets>
-    </PackageReference>
     <PackageReference Include="SauceControl.InheritDoc" Version="1.3.0">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
-    <PackageReference Include="StyleCop.Analyzers" Version="1.1.118">
-      <PrivateAssets>all</PrivateAssets>
-    </PackageReference>
   </ItemGroup>
 
   <ItemGroup>
@@ -53,4 +34,8 @@
     </AssemblyAttribute>
   </ItemGroup>
 
+  <PropertyGroup>
+    <AnalysisMode>AllEnabledByDefault</AnalysisMode>
+  </PropertyGroup>  
+
 </Project>
diff --git a/src/BBT.StrategyPattern/GenericStrategyProvider.cs b/src/BBT.StrategyPattern/GenericStrategyProvider.cs
@@ -33,10 +33,18 @@ public TStrategy GetStrategy(TCriterion criterion)
             // If no strategies for TStrategy can be found.
             if (!strategies.Any())
             {
-                throw new InvalidOperationException($"No strategies of {typeof(TStrategy).Name} are available from the locator.");
+                throw new InvalidOperationException($"No strategies of type {typeof(TStrategy).Name} are available from the locator.");
             }
 
-            return strategies.Single(x => x.IsResponsible(criterion));
+            var strategy = strategies.SingleOrDefault(x => x.IsResponsible(criterion));
+
+            // If no strategy responsible for TCriterion can be found.
+            if (strategy == null)
+            {
+                throw new InvalidOperationException($"No strategy of type {typeof(TStrategy).Name} available from the locator being responsible for criterion of type {typeof(TCriterion).Name}.");
+            }
+
+            return strategy;
         }
     }
 }