tests/heredoc.scm: Add test for (enable-syntax) macro

Test both compiled and non-compiled variants of the test in order to
stress the scenarios of *when* the read-macro is set.

Also change the (eval-when ...) case used:
- "compile": for when the code is being compiled only, and before its
  execution;
- "eval": for the the code is being evaluated only, during its
  execution.

Also from the Guile manual (via 'info (guile)Loading'):

    Changing ‘current-reader’ is typically useful to introduce local
    syntactic changes, such that code following the ‘fluid-set!’ call
    is read using the newly installed reader.  The ‘current-reader’
    change should take place at evaluation time when the code is
    evaluated, or at compilation time when the code is compiled:

         (eval-when (compile eval)
           (fluid-set! current-reader my-own-reader))

    The ‘eval-when’ form above ensures that the ‘current-reader’ change
    occurs at the right time.

1 files changed, 13 insertions, 1 deletions

diff --git a/tests/heredoc.scm b/tests/heredoc.scm
index e368119..931b7a2 100644
--- a/tests/heredoc.scm
+++ b/tests/heredoc.scm
@@ -1,5 +1,6 @@
 (use-modules
   ((xyz euandreh heredoc) #:prefix heredoc:)
+  ((language tree-il) #:prefix tree-il:)
   ((srfi srfi-64) #:prefix t:))
 (heredoc:enable-syntax)
 
@@ -315,6 +316,16 @@ fi
                     fi
                     """#)))
 
+(define (test-enable-syntax)
+  (t:test-group "enable-syntax"
+    (t:test-equal '(read-hash-extend #\"
+                                    (@ (xyz euandreh heredoc)
+                                       reader))
+                  (tree-il:tree-il->scheme
+                   (macroexpand
+                     '(heredoc:enable-syntax))))))
+
+
 (define test-fns
   (list
    test-extract-single-line-indentation
@@ -322,7 +333,8 @@ fi
    test-maximum-indentation
    test-trim-indentation
    test-non-quote-chars?
-   test-reader))
+   test-reader
+   test-enable-syntax))
 
 (define (main)
   (t:test-begin "heredoc")