diff --git a/R/use_crate.R b/R/use_crate.R
index cea33920..66496a7c 100644
--- a/R/use_crate.R
+++ b/R/use_crate.R
@@ -52,27 +52,33 @@ use_crate <- function(
   check_bool(optional)
   check_string(path)
 
+  if (!is.null(version) && !is.null(git)) {
+    cli::cli_abort(
+      "Cannot specify a git URL ('{git}') with a version ('{version}').",
+      class = "rextendr_error"
+    )
+  }
+
   if (!is.null(version)) {
     crate <- paste0(crate, "@", version)
   }
 
-  # combine main options
-  cargo_add_opts <- list(
-    "--features" = paste0(features, collapse = " "),
-    "--git" = git,
-    "--optional" = tolower(as.character(optional))
-  )
+  if (!is.null(features)) {
+    features <- c(
+      "--features",
+      paste(crate, features, sep = "/", collapse = ",")
+    )
+  }
 
-  # clear empty options
-  cargo_add_opts <- purrr::discard(cargo_add_opts, rlang::is_empty)
+  if (!is.null(git)) {
+    git <- c("--git", git)
+  }
 
-  # combine option names and values into single strings
-  adtl_args <- unname(purrr::imap_chr(
-    cargo_add_opts,
-    function(x, i) {
-      paste(i, paste0(x, collapse = " "))
-    }
-  ))
+  if (optional) {
+    optional <- "--optional"
+  } else {
+    optional <- NULL
+  }
 
   # get rust directory in project folder
   root <- rprojroot::find_package_root_file(path = path)
@@ -86,7 +92,7 @@ use_crate <- function(
   # run the commmand
   processx::run(
     "cargo",
-    c("add", crate, adtl_args),
+    c("add", crate, features, git, optional),
     echo_cmd = TRUE,
     wd = rust_folder
   )
diff --git a/tests/testthat/test-use_crate.R b/tests/testthat/test-use_crate.R
new file mode 100644
index 00000000..b3419279
--- /dev/null
+++ b/tests/testthat/test-use_crate.R
@@ -0,0 +1,97 @@
+test_that("use_crate() adds dependency to package or workspace", {
+  skip_if_not_installed("usethis")
+
+  path <- local_package("testpkg")
+
+  # capture setup messages
+  withr::local_options(usethis.quiet = FALSE)
+
+  use_extendr(path, quiet = TRUE)
+
+  use_crate(
+    "serde",
+    features = "derive",
+    version = "1.0.1",
+    path = path
+  )
+
+  metadata <- read_cargo_metadata(path)
+
+  dependency <- metadata[["packages"]][["dependencies"]][[1]]
+  dependency <- dependency[dependency[["name"]] == "serde", ]
+
+  expect_equal(dependency[["name"]], "serde")
+
+  expect_equal(dependency[["features"]][[1]], "derive")
+
+  expect_equal(dependency[["req"]], "^1.0.1")
+})
+
+test_that("use_crate() errors when user passes git and version arguments", {
+  skip_if_not_installed("usethis")
+
+  path <- local_package("testpkg")
+
+  # capture setup messages
+  withr::local_options(usethis.quiet = FALSE)
+
+  use_extendr(path, quiet = TRUE)
+
+  fn <- function() {
+    use_crate(
+      "serde",
+      git = "https://github.com/serde-rs/serde",
+      version = "1.0.1"
+    )
+  }
+
+  expect_error(fn(), class = "rextendr_error")
+})
+
+test_that("use_crate(optional = TRUE) adds optional dependency", {
+  skip_if_not_installed("usethis")
+
+  path <- local_package("testpkg")
+
+  # capture setup messages
+  withr::local_options(usethis.quiet = FALSE)
+
+  use_extendr(path, quiet = TRUE)
+
+  use_crate(
+    "serde",
+    optional = TRUE,
+    path = path
+  )
+
+  metadata <- read_cargo_metadata(path)
+
+  dependency <- metadata[["packages"]][["dependencies"]][[1]]
+  dependency <- dependency[dependency[["name"]] == "serde", ]
+
+  expect_identical(dependency[["optional"]], TRUE)
+})
+
+test_that("use_crate(git = <url>) adds dependency with git source", {
+  skip_if_not_installed("usethis")
+
+  path <- local_package("testpkg")
+
+  # capture setup messages
+  withr::local_options(usethis.quiet = FALSE)
+
+  use_extendr(path, quiet = TRUE)
+
+  use_crate(
+    "serde",
+    git = "https://github.com/serde-rs/serde",
+    path = path
+  )
+
+  metadata <- read_cargo_metadata(path)
+
+  dependency <- metadata[["packages"]][["dependencies"]][[1]]
+  dependency <- dependency[dependency[["name"]] == "serde", ]
+
+  expect_equal(dependency[["source"]], "git+https://github.com/serde-rs/serde")
+})