From 383a9434c410b42eb1c823a7ecadd73304b0935d Mon Sep 17 00:00:00 2001
From: OlivierHnt <38465572+OlivierHnt@users.noreply.github.com>
Date: Wed, 2 Oct 2024 10:46:40 -0400
Subject: [PATCH] Add test

---
 test/interval_tests/trigonometric.jl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/test/interval_tests/trigonometric.jl b/test/interval_tests/trigonometric.jl
index 055617776..19235c61d 100644
--- a/test/interval_tests/trigonometric.jl
+++ b/test/interval_tests/trigonometric.jl
@@ -39,6 +39,11 @@ end
     @test issubset_interval(cos(interval(BigFloat, 0.5, 8.5)), cos(interval(0.5, 8.5)))
     @test issubset_interval(cos(interval(BigFloat, -4.5, 0.1)), cos(interval(-4.5, 0.1)))
     @test issubset_interval(cos(interval(BigFloat, 1.3, 6.3)), cos(interval(1.3, 6.3)))
+
+    k = [interval(0.0,0.0625), interval(0.0625,0.125), interval(0.0,0.125)]
+    x = (k[1] * 4 + k[2] * 4 + k[3] * 4)
+    @test isequal_interval(cos(2 * π * x), interval(-1, 1))
+    @test isequal_interval(cospi(2x), interval(-1, 1))
 end
 
 @testset "sinpi" begin