diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4ff86d1..12e8b04 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -3,7 +3,7 @@
 
 build-rkorapclient-on-stable:
   extends: .install-rkorapclient
-  image: ubuntu:latest
+  image: rocker/tidyverse
   cache:
     key: rkorapclient-ubuntu-stable
     paths:
@@ -12,6 +12,8 @@
     - rlib/
   script:
     - start_section testing "Testing RKorAPClient"
-    - R -q -e 'library(RKorAPClient); testthat::test_dir("tests/testthat")'
+    - echo -e "apt-cache\nccache\nrlib" >> .Rbuildignore
+    - R -q -e "devtools::check(args = c('--no-examples'))"
+    - R -q -e 'devtools::test()'
     - end_section testing
 
diff --git a/ci/install-rkorapclient-ci.yml b/ci/install-rkorapclient-ci.yml
index 6e46c8b..f66c926 100644
--- a/ci/install-rkorapclient-ci.yml
+++ b/ci/install-rkorapclient-ci.yml
@@ -42,15 +42,12 @@
     - ln -s $(which ccache) /usr/local/sbin/gcc
     - ln -s $(which ccache) /usr/local/sbin/g++
     - end_section install_linux_packages
-
-  script:
     - start_section installing "Installing RKorAPClient from source"
     - export PATH=/usr/local/sbin:$PATH
     - R -q -e "install.packages('pak', dependencies=TRUE)"
-    - R -q -e "pak::pak('ggplot2', 'RKorAPClient', dependencies=TRUE)"
+    - R -q -e "pak::pak(c('devtools', 'RKorAPClient'), dependencies=TRUE)"
     - end_section installing
     - start_section linstalling "Installing RKorAPClient from source"
     - R -q -e 'pak::pak(".")'
     - ccache -s
     - end_section linstalling
-
diff --git a/tests/testthat/test-collocations.R b/tests/testthat/test-collocations.R
index 60052a6..b0c7a7a 100644
--- a/tests/testthat/test-collocations.R
+++ b/tests/testthat/test-collocations.R
@@ -48,7 +48,7 @@
 
 
 test_that("mergeDuplicateCollocatesWorksAsExpected", {
-  ldf <- tibble(
+  ldf <- tibble::tibble(
     node = c("focus(in [tt/p=NN] {[tt/l=nehmen]})"),
     collocate = c("Anspruch"),
     label = c(""),
@@ -71,7 +71,7 @@
     logDice = c(11.6899933757298),
     ll = c(3717716.74208791)
   )
-  rdf <- tibble(
+  rdf <- tibble::tibble(
     node = c("focus({[tt/l=nehmen] in} [tt/p=NN])"),
     collocate = c("Anspruch"),
     label = c(""),
diff --git a/tests/testthat/test-misc.R b/tests/testthat/test-misc.R
index c87dea4..a5b73de 100644
--- a/tests/testthat/test-misc.R
+++ b/tests/testthat/test-misc.R
@@ -219,7 +219,7 @@
       class = "data.frame",
       row.names = c(NA,-14L)
     )
-    gpt <- df %>% ggplot(aes(year, ipm, fill = condition, color = condition)) +
+    gpt <- df %>% ggplot2::ggplot(ggplot2::aes(year, ipm, fill = condition, color = condition)) +
       geom_freq_by_year_ci()
     labels <- if ("get_labs" %in% getNamespaceExports("ggplot2")) {
       ggplot2::get_labs(gpt)