diff --git a/tests/testthat/_snaps/style_helpers.md b/tests/testthat/_snaps/style_helpers.md
new file mode 100644
index 0000000..3a0aea8
--- /dev/null
+++ b/tests/testthat/_snaps/style_helpers.md
@@ -0,0 +1,16 @@
+# trbl() constructs correct data
+
+    `top` must be a number or `NULL`, not the string "a".
+
+---
+
+    `right` must be a number or `NULL`, not the string "a".
+
+---
+
+    `bottom` must be a number, not the string "a".
+
+---
+
+    `left` must be a number or `NULL`, not the string "a".
+
diff --git a/tests/testthat/test-style.R b/tests/testthat/test-style.R
index 81ed3de..c583ccd 100644
--- a/tests/testthat/test-style.R
+++ b/tests/testthat/test-style.R
@@ -128,7 +128,9 @@ test_that("style checks it's inputs", {
   expect_snapshot_error(style(background = TRUE))
   expect_silent(s <- style(background = NA))
   expect_type(s$background, "character")
-  expect_silent(s <- style(background = linearGradient()))
+  if ("linearGradient" %in% getNamespaceExports("grid")) {
+    expect_silent(s <- style(background = linearGradient()))
+  }
 
   # Border
   expect_silent(s <- style(border = "red"))
diff --git a/tests/testthat/test-style_helpers.R b/tests/testthat/test-style_helpers.R
new file mode 100644
index 0000000..7b9d700
--- /dev/null
+++ b/tests/testthat/test-style_helpers.R
@@ -0,0 +1,62 @@
+test_that("modifiers are constructed correctly", {
+  x <- relative(1)
+  expect_s3_class(x, "marquee_relative")
+  expect_true(is_relative(x))
+  expect_true(is_modifier(x))
+  expect_type(x, "list")
+  expect_equal(x[[1]], 1)
+
+  x <- em(1)
+  expect_s3_class(x, "marquee_em")
+  expect_true(is_em(x))
+  expect_true(is_modifier(x))
+  expect_type(x, "list")
+  expect_equal(x[[1]], 1)
+
+  x <- rem(1)
+  expect_s3_class(x, "marquee_rem")
+  expect_true(is_rem(x))
+  expect_true(is_modifier(x))
+  expect_type(x, "list")
+  expect_equal(x[[1]], 1)
+})
+
+test_that("trbl() constructs correct data", {
+  expect_equal(trbl(1), trbl(1, 1, 1, 1))
+  expect_equal(trbl(1, 2), trbl(1, 2, 1, 2))
+  expect_equal(trbl(1, 2, 3), trbl(1, 2, 3, 2))
+
+  expect_snapshot_error(trbl("a", 1, 1, 1))
+  expect_snapshot_error(trbl(1, "a", 1, 1))
+  expect_snapshot_error(trbl(1, 1, "a", 1))
+  expect_snapshot_error(trbl(1, 1, 1, "a"))
+
+  expect_silent(trbl(relative(1), 1, 1, 1))
+  expect_silent(trbl(1, em(1), 1, 1))
+  expect_silent(trbl(1, 1, rem(1), 1))
+
+  box <- trbl(1, relative(1), em(1), rem(1))
+  expect_s3_class(box, "marquee_trbl")
+  expect_true(is_trbl(box))
+  expect_equal(box[[1]], 1)
+  expect_equal(box[[2]], relative(1))
+  expect_equal(box[[3]], em(1))
+  expect_equal(box[[4]], rem(1))
+})
+
+test_that("skip_inherit() works with different types", {
+  expect_s3_class(skip_inherit(1), "marquee_skip_inherit")
+  expect_s3_class(skip_inherit(relative(1)), "marquee_skip_inherit")
+  expect_s3_class(skip_inherit(em(1)), "marquee_skip_inherit")
+  expect_s3_class(skip_inherit(rem(1)), "marquee_skip_inherit")
+
+  expect_s3_class(skip_inherit(relative(1)), "marquee_relative")
+  expect_s3_class(skip_inherit(em(1)), "marquee_em")
+  expect_s3_class(skip_inherit(rem(1)), "marquee_rem")
+
+  box <- skip_inherit(trbl(1, 2, 3, 4))
+  expect_s3_class(box[[1]], "marquee_skip_inherit")
+  expect_s3_class(box[[2]], "marquee_skip_inherit")
+  expect_s3_class(box[[3]], "marquee_skip_inherit")
+  expect_s3_class(box[[4]], "marquee_skip_inherit")
+})