Added tests for the new "non_existing" options

* Test "11" ensures that non-existing keys are replaced with the key itself when the option is set to "key" (e.g., '\acr{RL}' becomes 'RL').
* Test "12" ensures that non-existing keys are replaced with "??" when the option is set to "??".

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: acronymsdown
 Type: Package
 Title: Acronyms and Glossaries Support for RMarkdown
-Version: 0.8.0
+Version: 0.9.0
 Author: Remy Chaput
 Maintainer: remy chaput <rchaput.pro@gmail.com>
 Description: Adds support for list of acronyms (or glossaries) for RMarkdown

tests/11-missing-key/expected.md

@@ -0,0 +1,7 @@
+# List Of Acronyms {#acronyms_HEADER_LOA .loa}
+
+# Introduction {#intro}
+
+This paragraph mentions RL for the first time.
+
+And now, in this paragraph, RL is in short form.

tests/11-missing-key/input.Rmd

@@ -0,0 +1,16 @@
+---
+output:
+  md_document:
+    pandoc_args:
+      - !expr acronymsdown::add_filter()
+      - --wrap=preserve
+    variant: markdown
+acronyms:
+  non_existing: "key"
+---
+
+# Introduction {#intro}
+
+This paragraph mentions \acr{RL} for the first time.
+
+And now, in this paragraph, \acr{RL} is in short form.

tests/12-missing-??/expected.md

@@ -0,0 +1,7 @@
+# List Of Acronyms {#acronyms_HEADER_LOA .loa}
+
+# Introduction {#intro}
+
+This paragraph mentions ?? for the first time.
+
+And now, in this paragraph, ?? is in short form.

tests/12-missing-??/input.Rmd

@@ -0,0 +1,16 @@
+---
+output:
+  md_document:
+    pandoc_args:
+      - !expr acronymsdown::add_filter()
+      - --wrap=preserve
+    variant: markdown
+acronyms:
+  non_existing: "??"
+---
+
+# Introduction {#intro}
+
+This paragraph mentions \acr{RL} for the first time.
+
+And now, in this paragraph, \acr{RL} is in short form.

tests/test_rmarkdown.R

@@ -36,7 +36,9 @@ folders <- c(
   "07-multiple-external-yaml",
   "08-style-short-long",
   "09-style-footnote",
-  "10-no-links"
+  "10-no-links",
+  "11-missing-key",
+  "12-missing-??"
 )
 
 for (folder in folders) {