fix term ordering issue with Sym < Term

Author: shashi

src/simplify.jl

@@ -62,9 +62,9 @@ function <ₑ(a::Sym, b::Term)
             # both subterms are terms, so it's definitely firster
             return true
         elseif n1
-            return a <ₑ args[1]
+            return isequal(a, args[1]) || a <ₑ args[1]
         elseif n2
-            return a <ₑ args[2]
+            return isequal(a, args[2]) || a <ₑ args[2]
         else
             # both arguments are not numbers
             # This case when a <ₑ Term(^, [1,-1])

test/order.jl

@@ -63,3 +63,13 @@ end
     @test a(t) <ₑ b(t)
     @test !(b(t) <ₑ a(t))
 end
+
+@testset "Sym vs Term" begin
+    @syms x
+
+    @test x <ₑ (3 + x) && !((3 + x) <ₑ x)
+    @test x^2 <ₑ y && !(y <ₑ x^2)
+
+    # a nice consequence
+    @test simplify(x/(x+3) + 3/(x+3)) == 1
+end