Correct multiarg method tests and add saturating

Author: BioTurboNick

test/runtests.jl

@@ -398,15 +398,20 @@ end
 end
 
 @testset "multiargument methods" begin
-    @test @checked(1 + 4 + 5) == 10
-    @test_throws OverflowError @checked(typemax(Int) + 1 + 4 + 5)
-    @test_throws OverflowError @checked(1 + 4 + 5 + typemax(Int))
-    @test @checked(1.0 + 4 + 5 + typemax(Int)) == 9.223372036854776e18
+    @test @checked(+(1, 4, 5)) == 10
+    @test_throws OverflowError @checked(+(typemax(Int), 1, 4, 5))
+    @test_throws OverflowError @checked(+(1, 4, 5, typemax(Int)))
+    @test @checked(+(1.0, 4, 5, typemax(Int))) == 9.223372036854776e18
 
-    @test @unchecked(1 + 4 + 5) == 10
-    @test @unchecked(typemax(Int) + 1 + 4 + 5) == 10 + typemax(Int)
-    @test @unchecked(1 + 4 + 5 + typemax(Int)) == 10 + typemax(Int)
-    @test @checked(1.0 + 4 + 5 + typemax(Int)) == 9.223372036854776e18
+    @test @unchecked(+(1, 4, 5)) == 10
+    @test @unchecked(+(typemax(Int), 1, 4, 5)) == 10 + typemax(Int)
+    @test @unchecked(+(1, 4, 5, typemax(Int))) == 10 + typemax(Int)
+    @test @unchecked(+(1.0, 4, 5, typemax(Int))) == 9.223372036854776e18
+
+    @test @saturating(+(1, 4, 5)) == 10
+    @test @saturating(+(typemax(Int), 1, 4, 5)) == typemax(Int)
+    @test @saturating(+(1, 4, 5, typemax(Int))) == typemax(Int)
+    @test @saturating(+(1.0, 4, 5, typemax(Int))) == 9.223372036854776e18
 end
 
 using SaferIntegers