Add tests and NEWS.

NEWS.md

@@ -1,5 +1,7 @@
 # pkgdown (development version)
 
+* The language of the site is set from the first `Language:` in the `DESCRIPTION` if it is available and no other language is specified (@jonthegeek, #2808).
+
 # pkgdown 2.1.1
 
 * Added keyboard shortcut, `/`, to focus search bar (#2423)

tests/testthat/assets/reference-language/one/DESCRIPTION

@@ -0,0 +1,7 @@
+Package: testpackage
+Version: 1.0.0
+Title: A test package
+Description: A test package
+Authors@R: person("Hadley Wickham")
+RoxygenNote: 7.3.1
+Language: fr

tests/testthat/assets/reference-language/two/DESCRIPTION

@@ -0,0 +1,7 @@
+Package: testpackage
+Version: 1.0.0
+Title: A test package
+Description: A test package
+Authors@R: person("Hadley Wickham")
+RoxygenNote: 7.3.1
+Language: en-US, fr

tests/testthat/test-package.R

@@ -118,3 +118,32 @@ test_that("malformed figures fail gracefully", {
   expect_null(rd_lifecycle("{\\figure{deprecated.svg}}"))
   expect_null(rd_lifecycle("{\\figure{}}"))
 })
+
+# language ---------------------------------------------------------------------
+
+test_that("as_pkgdown sets language", {
+  # Default
+  pkg <- as_pkgdown(test_path("assets/reference"))
+  expect_equal(
+    pkg$lang,
+    "en"
+  )
+  # Single language specified in DESCRIPTION
+  pkg <- as_pkgdown(test_path("assets/reference-language/one"))
+  expect_equal(
+    pkg$lang,
+    "fr"
+  )
+  # Two languages specified in DESCRIPTION
+  pkg <- as_pkgdown(test_path("assets/reference-language/two"))
+  expect_equal(
+    pkg$lang,
+    "en-US"
+  )
+  # Language specified in _pkgdown.yml or override.
+  pkg <- as_pkgdown(test_path("assets/reference-language/two"), override = list(lang = "en-GB"))
+  expect_equal(
+    pkg$lang,
+    "en-GB"
+  )
+})