Check for warnings in examples and tests

.github/workflows/check-no-warnings.yaml

@@ -0,0 +1,48 @@
+# execute all examples and tests with warnings turned into errors to look for new warnings
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: check-no-warnings
+
+jobs:
+   check-no-warnings:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          pak-version: devel
+          extra-packages: |
+            any::devtools
+            local::.
+
+      - name: Run examples
+        run: |
+          options(crayon.enabled = TRUE,  warn = 2L)
+          devtools::run_examples(fresh = TRUE, run_dontrun = TRUE, run_donttest = TRUE)
+        shell: Rscript {0}
+
+      - name: Run Tests
+        run: |
+            options(crayon.enabled = TRUE)
+            pkgload::load_all()
+            # this workaround needed to play nicely with parallel testing
+            # see: https://github.com/r-lib/testthat/issues/1912
+            test_script_paths <- testthat::find_test_scripts("tests/testthat")
+            test_with_warning_as_error <- function(path) {
+              withr::local_options(list(warn = 2L))
+              testthat::test_file(path, stop_on_failure = TRUE, stop_on_warning = TRUE)
+            }
+            purrr::walk(test_script_paths, test_with_warning_as_error)
+        shell: Rscript {0}