Add test with accepted_kwargs as Val type

test/func.jl

@@ -305,5 +305,57 @@ end
     @test v2 ≈ a2 * A * u2 + b2 * w2
     @test v1 ≈ a1 * A * u1 + b1 * w1
     @test v1 + v2 ≈ (a1 * A * u1 + b1 * w1) + (a2 * A * u2 + b2 * w2)
+
+    ## Do the same with Val((:scale,))
+
+    L = FunctionOperator(f, u, u; p = zero(p), t = zero(t), batch = true,
+        accepted_kwargs = Val((:scale,)), scale = 1.0)
+
+    @test_throws ArgumentError FunctionOperator(
+        f, u, u; p = zero(p), t = zero(t), batch = true,
+        accepted_kwargs = Val((:scale,)))
+
+    @test size(L) == (N, N)
+
+    ans = @. u * p * t * scale
+    @test L(u, p, t; scale) ≈ ans
+    v = copy(u)
+    @test L(v, u, p, t; scale) ≈ ans
+
+    # test that output isn't accidentally mutated by passing an internal cache.
+
+    A = Diagonal(p * t * scale)
+    u1 = rand(N, K)
+    u2 = rand(N, K)
+
+    v1 = L * u1
+    @test v1 ≈ A * u1
+    v2 = L * u2
+    @test v2 ≈ A * u2
+    @test v1 ≈ A * u1
+    @test v1 + v2 ≈ A * (u1 + u2)
+
+    v1 .= 0.0
+    v2 .= 0.0
+
+    mul!(v1, L, u1)
+    @test v1 ≈ A * u1
+    mul!(v2, L, u2)
+    @test v2 ≈ A * u2
+    @test v1 ≈ A * u1
+    @test v1 + v2 ≈ A * (u1 + u2)
+
+    v1 = rand(N, K)
+    w1 = copy(v1)
+    v2 = rand(N, K)
+    w2 = copy(v2)
+    a1, a2, b1, b2 = rand(4)
+
+    mul!(v1, L, u1, a1, b1)
+    @test v1 ≈ a1 * A * u1 + b1 * w1
+    mul!(v2, L, u2, a2, b2)
+    @test v2 ≈ a2 * A * u2 + b2 * w2
+    @test v1 ≈ a1 * A * u1 + b1 * w1
+    @test v1 + v2 ≈ (a1 * A * u1 + b1 * w1) + (a2 * A * u2 + b2 * w2)
 end
 #