Add failing unit tests, seems stream is not 100%

hall.scm

@@ -31,7 +31,8 @@
          (tests ((directory
                    "tests"
                    ((scheme-file "test-eastasian-locale")
-                    (scheme-file "test-uniseg")))))
+                    (scheme-file "test-uniseg")
+                    (scheme-file "test-graphemes-stream")))))
          (programs
            ((directory
               "scripts"

tests/test-graphemes-stream.scm

@@ -0,0 +1,54 @@
+(define-module (tests test-graphemes-stream)
+  #:use-module (uniseg graphemes stream)
+  #:use-module (srfi srfi-41)
+  #:use-module (srfi srfi-64))
+
+(test-begin "tests-graphemes-stream")
+
+;; silly double-em dash
+(define stream (string->grapheme-stream "Trans 🏳️‍⚧️ rights are human rights⸺and that's a promise!"))
+
+(define* (advance-stream! #:optional (times 1))
+  (for-each
+   (λ (_)
+     (set! stream (stream-cdr stream)))
+   (make-list times)))
+
+(advance-stream! 6)
+
+(define trans-flag-grapheme (stream-car stream))
+
+(test-equal "Trans flag stream is correct"
+  "🏳️‍⚧️" (grapheme-string trans-flag-grapheme))
+
+(test-equal "Trans flag is width 2"
+  2 (grapheme-width trans-flag-grapheme))
+
+(advance-stream! 2)
+
+(define r-grapheme (stream-car stream))
+
+(test-equal "r in rights is in correct place"
+  "r" (grapheme-string r-grapheme))
+
+(test-equal "r is width 1"
+  1 (grapheme-width r-grapheme))
+
+(advance-stream! 23)
+
+(define double-em-dash-grapheme (stream-car stream))
+
+(test-equal "double-em-dash is in right place"
+  "⸺" (grapheme-string double-em-dash-grapheme))
+
+(test-equal "double-em-dash is double-width"
+  2 (grapheme-width double-em-dash-grapheme))
+
+(advance-stream!)
+
+(define a-grapheme (stream-car stream))
+
+(test-equal "advancing one goes to the a"
+  "a" (grapheme-string a-grapheme))
+
+(test-end "tests-graphemes-stream")

uniseg/graphemes/stream.scm

@@ -8,19 +8,22 @@
   #:export (make-grapheme
             grapheme?
             grapheme-glyphs
+            grapheme-string
             grapheme-width
-            grapheme-sentence-end?
-            grapheme-word-end?
             string->grapheme-stream
             input->grapheme-stream))
 
-;; TODO: uniseg also does word and sentence boundaries. These state machines could be implemented if we wanted to.
+;; TODO: the golang uniseg also does word and sentence boundaries. These state machines could be implemented if we wanted to.
 (define-immutable-record-type <grapheme>
   (make-grapheme glyphs width)
   grapheme?
   (glyphs grapheme-glyphs)
   (width grapheme-width))
 
+(define (grapheme-string grapheme)
+  "Given a grapheme, construct a string representing it."
+  (list->string (grapheme-glyphs grapheme)))
+
 (define (string->grapheme-stream str)
   "Given a string, create a (lazy) stream of graphemes."
   (with-input-from-string str