added isapprox method for UniformScaling and tests (#18870)

* added isapprox method for UniformScaling and tests

Author: lbollar

base/linalg/uniformscaling.jl

@@ -151,3 +151,6 @@ inv(J::UniformScaling) = UniformScaling(inv(J.λ))
 ./(J::UniformScaling,x::Number) = UniformScaling(J.λ/x)
 
 ==(J1::UniformScaling,J2::UniformScaling) = (J1.λ == J2.λ)
+
+isapprox{T<:Number,S<:Number}(J1::UniformScaling{T}, J2::UniformScaling{S};
+                              rtol::Real=Base.rtoldefault(T,S), atol::Real=0) = isapprox(J1.λ, J2.λ, rtol=rtol, atol=atol)

test/linalg/uniformscaling.jl

@@ -18,13 +18,15 @@ srand(123)
     @test -one(UniformScaling(2)) == UniformScaling(-1)
 end
 
-@testset "istriu, istril, issymmetric, ishermitian" begin
+@testset "istriu, istril, issymmetric, ishermitian, isapprox" begin
     @test istriu(I)
     @test istril(I)
     @test issymmetric(I)
     @test issymmetric(UniformScaling(complex(1.0,1.0)))
     @test ishermitian(I)
     @test !ishermitian(UniformScaling(complex(1.0,1.0)))
+    @test isapprox(UniformScaling(4.00000000000001), UniformScaling(4.0))
+    @test isapprox(UniformScaling(4.32), UniformScaling(4.3); rtol=0.1, atol=0.01)
 end
 
 @testset "* and / with number" begin