## Check aderiv(), which is not easily assessed in the checker()
## framework of aaa.R:

test_that("Test suite aac.R",{

P <- as.mvp("1 + x + x^3 z + 4 x^2 y + 4 z^4")^3

expect_true(P==P)
expect_false(P!=P)

expect_true(P!=P+1)
expect_false(P==P+1)

expect_true(P/2 + P/2==P)
expect_true(P+P==P*2)
expect_true(P+P==2*P)

expect_true(is.zero(P-P))
expect_true(is.zero(P*0))
expect_true(is.zero(P*as.mvp(0)))

expect_true(P+1 ==  1+P)
expect_true(P-1 == -1+P)
expect_true(1-P == -P+1)

expect_error(P==1)
expect_error(P!=1)
expect_false(P!=P)
expect_error(P^P)
expect_error(P^-1)
expect_error(P/P)

expect_error(P<P)
expect_error(P<=P)
expect_error(P>P)
expect_error(P>=P)



expect_true(aderiv(P,x=1,y=2,z=3) == aderiv(P,z=3,x=1,y=2))

expect_true(drop(as.mvp("0")) + drop(as.mvp("1")) + drop(as.mvp("2")) == 3)

expect_true(aderiv(as.mvp("x^6 y"),x=2,y=1) == as.mvp("30 x^4"),label="aderiv")



})