test: cover r2size arithmetic sizes

Author: t-kalinowski

tests/testthat/test-sizes-arithmetic.R

@@ -0,0 +1,66 @@
+# Unit tests for size expression lowering/evaluation
+
+test_that("constant arithmetic in declared dims is evaluated", {
+  fn <- function(x) {
+    declare(type(x = double(2L + 3L)))
+    sum(x)
+  }
+  qfn <- quick(fn)
+
+  expect_error(
+    qfn(as.double(1:4)),
+    "length(x) must be 5, not 4",
+    fixed = TRUE
+  )
+  expect_identical(qfn(as.double(1:5)), 15)
+
+  fn_pow <- function(x) {
+    declare(type(x = double(2L^3L)))
+    sum(x)
+  }
+  qfn_pow <- quick(fn_pow)
+
+  expect_error(
+    qfn_pow(as.double(1:7)),
+    "length(x) must be 8, not 7",
+    fixed = TRUE
+  )
+  expect_identical(qfn_pow(as.double(1:8)), 36)
+})
+
+test_that("dim/length/nrow/ncol are supported in allocation sizes", {
+  vec <- function(x) {
+    declare(type(x = double(NA)))
+    out <- double(length(x) + 1L)
+    length(out)
+  }
+  expect_quick_identical(vec, list(as.double(1:3)), list(as.double(1)))
+
+  mat <- function(x) {
+    declare(type(x = double(NA, NA)))
+    out <- double(length(x) + 1L)
+    length(out)
+  }
+  expect_quick_identical(mat, list(matrix(as.double(1:12), nrow = 3, ncol = 4)))
+
+  mat_dims <- function(x) {
+    declare(type(x = double(NA, NA)))
+    out1 <- double(dim(x)[2L] + 1L)
+    out2 <- double(nrow(x) + ncol(x))
+    c(length(out1), length(out2))
+  }
+  expect_quick_identical(
+    mat_dims,
+    list(matrix(as.double(1:12), nrow = 3, ncol = 4)),
+    list(matrix(as.double(1:6), nrow = 2, ncol = 3))
+  )
+})
+
+test_that("dim(x)[axis] errors when axis exceeds rank", {
+  bad <- function(x) {
+    declare(type(x = double(NA, NA)))
+    double(dim(x)[3L])
+  }
+
+  expect_error(quick(bad), "insufficient rank", fixed = TRUE)
+})