Added tests for new added sqlserver dialect syntax.

Language/SQL/SimpleSQL/Pretty.lhs

@@ -254,6 +254,11 @@ Try to do this when this code is ported to a modern pretty printing lib.
 > scalarExpr d (OdbcFunc e) =
 >     text "{fn" <+> scalarExpr d e <> text "}"
 
+> scalarExpr d (Convert t e Nothing) =
+>     text "convert(" <> typeName t <> text "," <+> scalarExpr d e <> text ")"
+> scalarExpr d (Convert t e (Just i)) =
+>     text "convert(" <> typeName t <> text "," <+> scalarExpr d e <> text "," <+> text (show i) <> text ")"
+
 > unname :: Name -> String
 > unname (Name Nothing n) = n
 > unname (Name (Just (s,e)) n) =

tools/Language/SQL/SimpleSQL/LexerTests.lhs

@@ -318,8 +318,8 @@ the + or -.
 >     [ LexTest sqlserver {diOdbc = True} s t | (s,t) <-
 >     [("{}", [Symbol "{", Symbol "}"])
 >     ]]
->     ++ [LexFails sqlserver "{"
->        ,LexFails sqlserver "}"]
+>     ++ [LexFails sqlserver {diOdbc = False} "{"
+>        ,LexFails sqlserver {diOdbc = False} "}"]
 
 > combos :: [a] -> Int -> [[a]]
 > combos _ 0 = [[]]

tools/Language/SQL/SimpleSQL/ScalarExprs.lhs

@@ -5,7 +5,7 @@ Tests for parsing scalar expressions
 
 > import Language.SQL.SimpleSQL.TestTypes
 > import Language.SQL.SimpleSQL.Syntax
-
+  
 > scalarExprTests :: TestItem
 > scalarExprTests = Group "scalarExprTests"
 >     [literals
@@ -15,6 +15,7 @@ Tests for parsing scalar expressions
 >     ,dots
 >     ,app
 >     ,caseexp
+>     ,convertfun     
 >     ,operators
 >     ,parens
 >     ,subqueries
@@ -110,6 +111,16 @@ Tests for parsing scalar expressions
 
 >     ]
 
+> convertfun :: TestItem 
+> convertfun = Group "convert" $ map (uncurry (TestScalarExpr sqlserver))
+>     [("CONVERT(varchar, 25.65)"
+>      ,Convert (TypeName [Name Nothing "varchar"]) (NumLit "25.65") Nothing)
+>     ,("CONVERT(datetime, '2017-08-25')"
+>      ,Convert (TypeName [Name Nothing "datetime"]) (StringLit "'" "'" "2017-08-25") Nothing)
+>     ,("CONVERT(varchar, '2017-08-25', 101)"
+>      ,Convert (TypeName [Name Nothing "varchar"]) (StringLit "'" "'" "2017-08-25") (Just 101))
+>     ]
+
 > operators :: TestItem
 > operators = Group "operators"
 >     [binaryOperators