test-qgis-{help,run-algorithm}.R: add tests for alg deprecation warning

tests/testthat/test-qgis-help.R

@@ -70,3 +70,32 @@ test_that("algorithms with no outputs have zero-row qgis_get_output_specs()", {
   skip_if_not(has_qgis())
   expect_identical(nrow(qgis_get_output_specs("native:spatialiteexecutesql")), 0L)
 })
+
+test_that("Help functions & qgis_function() yield a warning with deprecated algorithms only", {
+  skip_if_not(has_qgis())
+  skip_if_not(qgis_using_json_output())
+  algs <- qgis_algorithms()
+  skip_if_not(
+    "deprecated" %in% colnames(algs) && sum(algs$deprecated) > 0,
+    paste(
+      "There are no deprecated algorithms available.",
+      "Rewrite this test to simulate deprecated algorithms."
+    )
+  )
+  local_edition(3) # if more than one warning pops up, it should be apparent from
+                   # testthat output (only the first warning is swallowed in the
+                   # third edition of testthat)
+
+  alg_deprecated <- sample(algs$algorithm[algs$deprecated], 1)
+  alg_non_deprecated <- sample(algs$algorithm[!algs$deprecated], 1)
+  expect_warning(capture.output(qgis_show_help(alg_deprecated)))
+  expect_no_warning(capture.output(qgis_show_help(alg_non_deprecated)))
+  expect_warning(qgis_get_description(alg_deprecated))
+  expect_no_warning(qgis_get_description(alg_non_deprecated))
+  expect_warning(qgis_get_argument_specs(alg_deprecated))
+  expect_no_warning(qgis_get_argument_specs(alg_non_deprecated))
+  expect_warning(qgis_get_output_specs(alg_deprecated))
+  expect_no_warning(qgis_get_output_specs(alg_non_deprecated))
+  expect_warning(qgis_function(alg_deprecated))
+  expect_no_warning(qgis_function(alg_non_deprecated))
+})

tests/testthat/test-qgis-run-algorithm.R

@@ -272,3 +272,29 @@ test_that(glue("qgis_run_algorithm() succeeds when it uses an aggregates input a
   expect_identical(ll_res$depth, depth_vals)
   expect_identical(ll_res$name[1], "a,f,k,p,u")
 })
+
+test_that("qgis_run_algorithm() yields a warning with a deprecated algorithm", {
+  skip_if_not(has_qgis())
+  skip_if_not(qgis_using_json_output())
+  algs <- qgis_algorithms()
+  skip_if_not(
+    "deprecated" %in% colnames(algs) && sum(algs$deprecated) > 0,
+    "There are no deprecated algorithms available."
+  )
+  skip_if_not(
+    "native:raisewarning" %in% algs$algorithm[algs$deprecated],
+    "'native:raisewarning' is not an available deprecated algorithm."
+  )
+  local_edition(3) # if more than one warning pops up, it should be apparent from
+                   # testthat output (only the first warning is swallowed in the
+                   # third edition of testthat)
+
+  suppressMessages(
+    expect_warning(
+      qgis_run_algorithm(
+        "native:raisewarning",
+        MESSAGE = "Some text than won't come back though."
+      )
+    )
+  )
+})