From 32dc5d893d0eb610f389a46058258131c77fce11 Mon Sep 17 00:00:00 2001
From: Reno <25192197+singularitti@users.noreply.github.com>
Date: Mon, 15 Nov 2021 23:53:15 -0500
Subject: [PATCH] Add "Test addition and subtraction"

---
 test/arithmetic.jl | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/test/arithmetic.jl b/test/arithmetic.jl
index 4a5c213..8e054d6 100644
--- a/test/arithmetic.jl
+++ b/test/arithmetic.jl
@@ -14,3 +14,16 @@ end
     @test a / 2 == EngineeringStress(0.5, 1, 1.5, 2, 2.5, 3)
     @test 2a / 2 == a
 end
+
+@testset "Test addition and subtraction" begin
+    a = EngineeringStrain(1:6)
+    b = -EngineeringStrain(1:1:6)
+    @test a - b == 2a
+    @test b - a == -2a
+    @test a + b == EngineeringStrain(zeros(6))
+    a = TensorStress(EngineeringStress(1:6))
+    b = -TensorStress(EngineeringStress(1:6))
+    @test a - b == 2a
+    @test b - a == -2a
+    @test a + b == TensorStress(zeros(3, 3))
+end