GetDeminfiedMethodNameFromSourceMap is never called with null inputs, removing the conditional checks and adding unit tests to (#35)

src/SourceMapToolkit.CallstackDeminifier/FunctionMapGenerator.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using Microsoft.Ajax.Utilities;
@@ -61,36 +62,42 @@ namespace SourcemapToolkit.CallstackDeminifier
 		/// <summary>
 		/// Gets the original name corresponding to a function based on the information provided in the source map.
 		/// </summary>
-		/// <returns></returns>
 		internal static string GetDeminifiedMethodNameFromSourceMap(FunctionMapEntry wrappingFunction, SourceMap sourceMap)
 		{
+			if (wrappingFunction == null)
+			{
+				throw new ArgumentNullException(nameof(wrappingFunction));
+			}
+
+			if (sourceMap == null)
+			{
+				throw new ArgumentNullException(nameof(sourceMap));
+			}
+
 			string methodName = null;
 
-			if (wrappingFunction?.Bindings != null && wrappingFunction.Bindings.Count > 0)
+			if (wrappingFunction.Bindings != null && wrappingFunction.Bindings.Count > 0)
 			{
 				if (wrappingFunction.Bindings.Count == 2)
 				{
 					MappingEntry objectProtoypeMappingEntry =
-						sourceMap?.GetMappingEntryForGeneratedSourcePosition(wrappingFunction.Bindings[0].SourcePosition);
+						sourceMap.GetMappingEntryForGeneratedSourcePosition(wrappingFunction.Bindings[0].SourcePosition);
 
 					methodName = objectProtoypeMappingEntry?.OriginalName;
 				}
 
 				MappingEntry mappingEntry =
-					sourceMap?.GetMappingEntryForGeneratedSourcePosition(wrappingFunction.Bindings.Last().SourcePosition);
+					sourceMap.GetMappingEntryForGeneratedSourcePosition(wrappingFunction.Bindings.Last().SourcePosition);
 
-				if (mappingEntry != null)
+				if (mappingEntry?.OriginalName != null)
 				{
-					if (mappingEntry.OriginalName != null)
+					if (methodName != null)
 					{
-						if (methodName != null)
-						{
-							methodName = methodName + "." + mappingEntry.OriginalName;
-						}
-						else
-						{
-							methodName = mappingEntry.OriginalName;
-						}
+						methodName = methodName + "." + mappingEntry.OriginalName;
+					}
+					else
+					{
+						methodName = mappingEntry.OriginalName;
 					}
 				}
 			}

tests/SourcemapToolkit.CallstackDeminifier.UnitTests/FunctionMapGeneratorUnitTests.cs

@@ -385,6 +385,30 @@ namespace SourcemapToolkit.CallstackDeminifier.UnitTests
 			Assert.AreEqual(22, functionMap[1].EndSourcePosition.ZeroBasedColumnNumber);
 		}
 
+		[TestMethod]
+		[ExpectedException(typeof(ArgumentNullException))]
+		public void GetDeminifiedMethodNameFromSourceMap_NullFunctionMapEntry_ThrowsException()
+		{
+			// Arrange
+			FunctionMapEntry functionMapEntry = null;
+			SourceMap sourceMap = MockRepository.GenerateStub<SourceMap>();
+
+			// Act
+			FunctionMapGenerator.GetDeminifiedMethodNameFromSourceMap(functionMapEntry, sourceMap);
+		}
+
+		[TestMethod]
+		[ExpectedException(typeof(ArgumentNullException))]
+		public void GetDeminifiedMethodNameFromSourceMap_NullSourceMap_ThrowsException()
+		{
+			// Arrange
+			FunctionMapEntry functionMapEntry = new FunctionMapEntry();
+			SourceMap sourceMap = null;
+
+			// Act
+			FunctionMapGenerator.GetDeminifiedMethodNameFromSourceMap(functionMapEntry, sourceMap);
+		}
+
 		[TestMethod]
 		public void GetDeminifiedMethodNameFromSourceMap_NoBinding_ReturnNullMethodName()
 		{
@@ -461,6 +485,50 @@ namespace SourcemapToolkit.CallstackDeminifier.UnitTests
 			sourceMap.VerifyAllExpectations();
 		}
 
+		[TestMethod]
+		public void GetDeminifiedMethodNameFromSourceMap_MatchingMappingMultipleBindingsMissingPrototypeMapping_ReturnsMethodName()
+		{
+			// Arrange
+			FunctionMapEntry functionMapEntry = new FunctionMapEntry
+			{
+				Bindings =
+					new List<BindingInformation>
+					{
+						new BindingInformation
+						{
+							SourcePosition = new SourcePosition {ZeroBasedLineNumber = 86, ZeroBasedColumnNumber = 52}
+						},
+						new BindingInformation
+						{
+							SourcePosition = new SourcePosition {ZeroBasedLineNumber = 88, ZeroBasedColumnNumber = 78}
+						}
+					}
+			};
+
+			SourceMap sourceMap = MockRepository.GenerateStub<SourceMap>();
+			sourceMap.Stub(
+				x =>
+					x.GetMappingEntryForGeneratedSourcePosition(
+						Arg<SourcePosition>.Matches(y => y.ZeroBasedLineNumber == 86 && y.ZeroBasedColumnNumber == 52)))
+				.Return(null);
+
+			sourceMap.Stub(
+				x =>
+					x.GetMappingEntryForGeneratedSourcePosition(
+						Arg<SourcePosition>.Matches(y => y.ZeroBasedLineNumber == 88 && y.ZeroBasedColumnNumber == 78)))
+				.Return(new MappingEntry
+				{
+					OriginalName = "baz",
+				});
+
+			// Act
+			string result = FunctionMapGenerator.GetDeminifiedMethodNameFromSourceMap(functionMapEntry, sourceMap);
+
+			// Assert
+			Assert.AreEqual("baz", result);
+			sourceMap.VerifyAllExpectations();
+		}
+
 		[TestMethod]
 		public void GetDeminifiedMethodNameFromSourceMap_MatchingMappingMultipleBindings_ReturnsMethodNameWithFullBinding()
 		{