fix failing unit tests

Author: Mpdreamz

src/Nest/Indices/Analyze/AnalyzeTokenFilters.cs

@@ -247,6 +247,10 @@ public AnalyzeTokenFiltersDescriptor Standard(Func<StandardTokenFilterDescriptor
 		public AnalyzeTokenFiltersDescriptor Stemmer(Func<StemmerTokenFilterDescriptor, IStemmerTokenFilter> selector) =>
 			AssignIfNotNull(selector?.Invoke(new StemmerTokenFilterDescriptor()));
 
+		/// <inheritdoc cref="IPredicateTokenFilter" />
+		public AnalyzeTokenFiltersDescriptor Predicate(Func<PredicateTokenFilterDescriptor, IPredicateTokenFilter> selector) =>
+			AssignIfNotNull(selector?.Invoke(new PredicateTokenFilterDescriptor()));
+
 		/// <summary>
 		/// Overrides stemming algorithms, by applying a custom mapping, then protecting these terms from being modified by stemmers. Must be placed
 		/// before any stemming filters.

src/Tests/Tests/Analysis/TokenFilters/TokenFilterTests.cs

@@ -935,6 +935,7 @@ public class MultiplexerTests : TokenFilterAssertionBase<MultiplexerTests>
 
 			public override object Json => new
 			{
+				type = "multiplexer",
 				filters = new[] { "lowercase", "lowercase, porter_stem" },
 				preserve_original = true
 			};
@@ -947,7 +948,7 @@ public class RemoveDuplicatesTests : TokenFilterAssertionBase<RemoveDuplicatesTe
 		{
 			public override FuncTokenFilters Fluent => (n, tf) => tf.RemoveDuplicates(n);
 			public override ITokenFilter Initializer => new RemoveDuplicatesTokenFilter { };
-			public override object Json => new { };
+			public override object Json => new { type = "remove_duplicates" };
 			public override string Name => "dupes";
 		}
 	}