add test

DESCRIPTION

@@ -214,3 +214,4 @@ Roxygen: list(markdown = TRUE)
 Config/testthat/edition: 3
 Config/testthat/parallel: true
 Config/Needs/website: easystats/easystatstemplate
+Config/Needs/check: stan-dev/cmdstanr

NEWS.md

@@ -16,6 +16,9 @@
   minimum required package version based on the SUGGEST field of the _insight_
   package, instead of the package that was calling the function.
 
+* Fixed issue in `get_modelmatrix()` for models from package *brms* with
+  special functions in the formula (like `mo()`).
+
 # insight 0.20.2
 
 ## New supported models

tests/testthat/test-brms.R

@@ -2,7 +2,7 @@ skip_on_cran()
 skip_if_offline()
 skip_on_os("mac")
 skip_if_not_installed("brms")
-skip_if_not_installed("httr")
+skip_if_not_installed("httr2")
 
 # Model fitting -----------------------------------------------------------
 
@@ -513,6 +513,14 @@ test_that("find_algorithm", {
   )
 })
 
+test_that("get_modelmatrix", {
+  out <- get_modelmatrix(m1)
+  expect_named(out, c("(Intercept)", "Age", "Base", "Trt1"))
+  m9 <- insight::download_model("brms_mo2")
+  skip_if(is.null(m9))
+  out <- get_modelmatrix(m9)
+  expect_named(out, c("(Intercept)", "gear"))
+})
 
 test_that("get_priors", {
   expect_equal(