fix test

Author: shashi

src/types.jl

@@ -131,7 +131,7 @@ struct FnType{X<:Tuple,Y} end
 (f::Sym{<:FnType})(args...) = term(f, args...)
 
 function (f::Sym)(args...)
-    error("Sym $f of type $F are not callable. " *
+    error("Sym $f is not callable. " *
           "Use @syms $f(var1, var2,...) to create it as a callable. " *
           "See ?@fun for more options")
 end

test/basics.jl

@@ -45,3 +45,8 @@ end
 
     @test rem2pi(a, RoundNearest) == Term{Real}(rem2pi, [a, RoundNearest])
 end
+
+@testset "err test" begin
+    @syms t()
+    @test_throws ErrorException t(2)
+end

test/order.jl

@@ -52,7 +52,7 @@ end
 end
 
 @testset "0-arg variable calls ordering" begin
-    @syms z ρ
+    @syms z() ρ()
 
     @test -1z() <ₑ ρ()
     @test !(ρ() <ₑ -1z())