test(quarto): fix failing test on windows

Output was:

```
  ── Failure ('test-tar_quarto.R:521:3'): tar_quarto() reruns if target changes in included file ──
  sort(basename(out)) (`actual`) not equal to sort(c("main.html", "main.qmd", "file1.qmd")) (`expected`).

  `actual`:   "file1.qmd" "file1.qmd" "main.html" "main.qmd"
  `expected`: "file1.qmd"             "main.html" "main.qmd"
```

Thus, `file1.qmd` were not detected as a duplicate of the other
`file1.qmd`. Probably because they have different paths. Thus, make
`unique` command apear later in chain (after `path_rel`). This way, we
should fix this issue.

R/tar_quarto_files.R

@@ -51,7 +51,7 @@ tar_quarto_files <- function(path = ".", profile = NULL) {
     tar_quarto_files_document(path)
   )
   for (field in c("sources", "output", "input")) {
-    out[[field]] <- sort(fs::path_rel(unique(as.character(out[[field]]))))
+    out[[field]] <- sort(unique(fs::path_rel(as.character(out[[field]]))))
     out[[field]] <- as.character(out[[field]])
   }
   out
@@ -72,13 +72,17 @@ tar_quarto_files_document <- function(path) {
     )
   }
 
-  # Collect data about input files.
+  # Collect data about input files. It seems that quarto only puts the main
+  # rendering file (in this case `path`) into `fileInformation`. Even though
+  # included files might include other files, they still appear in
+  # `includeMap$target` and not as an own `fileInformation` entry.
   for (myfile in names(info$fileInformation)) {
     out$input <- c(
       out$input,
       # `myfile` are relative paths starting from `path`.
       myfile,
-      # `includeMap` contains relative paths starting from `myfile`.
+      # `includeMap` contains relative paths starting from `myfile`. We can use
+      # `dirname(path)` here as this is the directory of `myfile`.
       file.path(
         dirname(path),
         info$fileInformation[[myfile]]$includeMap$target

tests/testthat/test-tar_quarto_files.R

@@ -89,15 +89,15 @@ targets::tar_test("tar_quarto_files() detects non-code dependencies", {
     "output_format: html",
     "---",
     "",
-    "{{< include \"text1.qmd\" >}}",
-    "",
-    "{{< include \"subdir/text2.qmd\" >}}"
+    "{{< include \"text1.qmd\" >}}"
   )
   writeLines(lines, file.path("report", "main.qmd"))
   lines <- c(
     "# First File",
     "",
-    "Some text here."
+    "Some text here.",
+    "",
+    "{{< include \"subdir/text2.qmd\" >}}"
   )
   writeLines(lines, file.path("report", "text1.qmd"))
   lines <- c(