Basic Symbolics tests -- pass!

Project.toml

@@ -24,8 +24,9 @@ Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
 QuadGK = "1fd47b50-473d-5c70-9696-f719f8f3bcdc"
 SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+Symbolics = "0c5d862f-8b57-4792-8d23-62f2024744c7"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 
 [targets]
-test = ["Aqua", "QuadGK", "SpecialFunctions", "Statistics", "Test", "Unitful"]
+test = ["Aqua", "QuadGK", "SpecialFunctions", "Statistics", "Symbolics", "Test", "Unitful"]

test/runtests.jl

@@ -1051,3 +1051,7 @@ end
     # JuliaLang/julia#30944
     @test range(0±0, step=1±.1, length=10) isa StepRangeLen
 end
+
+@testset "Symbolics" begin
+    include("symbolics.jl")
+end

test/symbolics.jl

@@ -0,0 +1,37 @@
+using Symbolics
+
+isapprox(x::Symbolics.Num, y::Symbolics.Num; rest...) = isequal(x, y)
+
+@testset "measurement" begin
+    @variables x, x_err
+
+    @test typeof(@inferred(measurement(x))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, 0))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, 1))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, 0.0))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, 1.0))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, big(0)))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, big(1)))) == Measurement{Num}
+    @test typeof(@inferred(measurement(x, x_err))) == Measurement{Num}
+    @test typeof(@inferred(measurement(0, x_err))) == Measurement{Num}
+    @test typeof(@inferred(measurement(0.0, x_err))) == Measurement{Num}
+    @test typeof(@inferred(measurement(big(0), x_err))) == Measurement{Num}
+
+    @test iszero(@inferred(measurement(x)).err)
+    @test @inferred(measurement(x)).tag === UInt64(0)
+    @test length(@inferred(measurement(x)).der) == 0
+    @test !(@inferred(measurement(x, x_err)).tag === UInt64(0))
+    @test length(@inferred(measurement(x, 0)).der) == 0
+    @test length(@inferred(measurement(x, x_err)).der) == 1
+end
+
+##### Mathematical Operations
+@testset "Addition" begin
+    @variables x_val, x_err, y_val, y_err
+
+    x = measurement(x_val, x_err)
+    y = measurement(y_val, y_err)
+
+    # abs2(v) === abs(x)^2, but maybe faster.
+    @test @inferred(x + y) ≈ measurement(x_val + y_val, sqrt(abs2(x_err) + abs2(y_err)))
+end