Add includeContext parameter to GetBestGuess

src/SIL.LCModel/DomainServices/AnalysisGuessServices.cs

@@ -631,7 +631,11 @@ public IAnalysis GetBestGuess(IWfiAnalysis wa)
 		/// True: Do lowercase matching only if the occurrence index is zero.
 		/// False: Do lowercase matching regardless of the occurrence index.
 		/// </param>
-		public IAnalysis GetBestGuess(AnalysisOccurrence occurrence, bool onlyIndexZeroLowercaseMatching = true)
+		/// <param name="includeContext">
+		/// True: Consider previous word when getting best guess.
+		/// False: Ignore previous word when getting best guess.
+		/// </param>
+		public IAnalysis GetBestGuess(AnalysisOccurrence occurrence, bool onlyIndexZeroLowercaseMatching = true, bool includeContext = true)
 		{
 			// first see if there is a relevant lowercase form of a sentence initial (non-lowercase) wordform
 			// TODO: make it look for the first word in the sentence...may not be at Index 0!
@@ -654,7 +658,7 @@ public IAnalysis GetBestGuess(AnalysisOccurrence occurrence, bool onlyIndexZeroL
 			if (ws == -1)
 				return new NullWAG(); // happens with empty translation lines
 			IAnalysis bestGuess;
-			IAnalysis previous = GetPreviousWordform(occurrence.Segment, occurrence.Index);
+			IAnalysis previous = includeContext ? GetPreviousWordform(occurrence.Segment, occurrence.Index) : m_nullWAG;
 			if (TryGetContextAwareGuess(occurrence.Analysis, lowercaseWf, previous, out bestGuess))
 				return bestGuess;
 			return new NullWAG();

tests/SIL.LCModel.Tests/DomainServices/AnalysisGuessServicesTests.cs

@@ -1388,6 +1388,8 @@ public void ExpectedContextAwareGloss_PreferContextedOverUncontexted()
 				// Make sure we get a contexted guess for occurrence instead of an uncontexted guess.
 				guessActual = setup.GuessServices.GetBestGuess(occurrence);
 				Assert.AreEqual(contextedApprovedGloss, guessActual);
+				guessActual = setup.GuessServices.GetBestGuess(occurrence, includeContext: false);
+				Assert.AreEqual(uncontextedApprovedGloss, guessActual);
 				// Verify uncontexted guess for sort.
 				var sorted_glosses = setup.GuessServices.GetSortedGlossGuesses(analysis);
 				Assert.AreEqual(2, sorted_glosses.Count);