Fixed: fail on non-leading whitespace in field chains

Author: bkoelman

src/JsonApiDotNetCore/Queries/Internal/Parsing/QueryTokenizer.cs

@@ -87,7 +87,7 @@ public IEnumerable<Token> EnumerateTokens()
                 }
                 else
                 {
-                    if (_textBuffer.Length == 0 && ch == ' ' && !_isInQuotedSection)
+                    if (ch == ' ' && !_isInQuotedSection)
                     {
                         throw new QueryParseException("Unexpected whitespace.");
                     }

test/JsonApiDotNetCoreTests/UnitTests/QueryStringParameters/FilterParseTests.cs

@@ -66,13 +66,16 @@ public void Reader_Is_Enabled(JsonApiQueryStringParameters parametersDisabled, b
     [InlineData("filter[posts]", "equals(author,'some')", "Attribute 'author' does not exist on resource type 'blogPosts'.")]
     [InlineData("filter[posts]", "lessThan(author,null)", "Attribute 'author' does not exist on resource type 'blogPosts'.")]
     [InlineData("filter", " ", "Unexpected whitespace.")]
+    [InlineData("filter", "contains(owner.displayName ,)", "Unexpected whitespace.")]
     [InlineData("filter", "contains(owner.displayName, )", "Unexpected whitespace.")]
     [InlineData("filter", "some", "Filter function expected.")]
     [InlineData("filter", "equals", "( expected.")]
     [InlineData("filter", "equals'", "Unexpected ' outside text.")]
     [InlineData("filter", "equals(", "Count function or field name expected.")]
     [InlineData("filter", "equals('1'", "Count function or field name expected.")]
     [InlineData("filter", "equals(count(posts),", "Count function, value between quotes, null or field name expected.")]
+    [InlineData("filter", "equals(owner..displayName,'')", "Count function or field name expected.")]
+    [InlineData("filter", "equals(owner.displayName.,'')", "Count function or field name expected.")]
     [InlineData("filter", "equals(title,')", "' expected.")]
     [InlineData("filter", "equals(title,null", ") expected.")]
     [InlineData("filter", "equals(null", "Field 'null' does not exist on resource type 'blogs'.")]