1 files changed, 207 insertions, 0 deletions
diff --git a/tests/test-custom-text-enclose-prepend.el b/tests/test-custom-text-enclose-prepend.el
new file mode 100644
index 00000000..e03375ff
--- /dev/null
+++ b/tests/test-custom-text-enclose-prepend.el
@@ -0,0 +1,207 @@
+;;; test-custom-text-enclose-prepend.el --- Tests for cj/--prepend-to-lines -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Tests for the cj/--prepend-to-lines function from custom-text-enclose.el
+;;
+;; This function prepends a prefix string to the beginning of each line in text.
+;; It preserves the structure of lines and handles trailing newlines correctly.
+;;
+;; Examples:
+;; Input:  "line1\nline2", prefix: "// "
+;; Output: "// line1\n// line2"
+;;
+;; Input:  "single", prefix: "> "
+;; Output: "> single"
+;;
+;; We test the NON-INTERACTIVE implementation (cj/--prepend-to-lines) to avoid
+;; mocking region selection. This follows our testing best practice of
+;; separating business logic from UI interaction.
+
+;;; Code:
+
+(require 'ert)
+(require 'testutil-general)
+
+;; Add modules directory to load path
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+
+;; Stub dependencies before loading the module
+(defvar cj/custom-keymap (make-sparse-keymap)
+  "Stub keymap for testing.")
+
+;; Now load the actual production module
+(require 'custom-text-enclose)
+
+;;; Test Helpers
+
+(defun test-prepend-to-lines (text prefix)
+  "Test cj/--prepend-to-lines on TEXT with PREFIX.
+Returns the transformed string."
+  (cj/--prepend-to-lines text prefix))
+
+;;; Normal Cases - Single Line
+
+(ert-deftest test-prepend-single-line ()
+  "Should prepend to single line."
+  (let ((result (test-prepend-to-lines "hello" "> ")))
+    (should (string= result "> hello"))))
+
+(ert-deftest test-prepend-single-line-comment ()
+  "Should prepend comment marker to single line."
+  (let ((result (test-prepend-to-lines "code here" "// ")))
+    (should (string= result "// code here"))))
+
+(ert-deftest test-prepend-single-line-bullet ()
+  "Should prepend bullet to single line."
+  (let ((result (test-prepend-to-lines "item" "- ")))
+    (should (string= result "- item"))))
+
+;;; Normal Cases - Multiple Lines
+
+(ert-deftest test-prepend-two-lines ()
+  "Should prepend to two lines."
+  (let ((result (test-prepend-to-lines "line1\nline2" "> ")))
+    (should (string= result "> line1\n> line2"))))
+
+(ert-deftest test-prepend-three-lines ()
+  "Should prepend to three lines."
+  (let ((result (test-prepend-to-lines "a\nb\nc" "* ")))
+    (should (string= result "* a\n* b\n* c"))))
+
+(ert-deftest test-prepend-many-lines ()
+  "Should prepend to many lines."
+  (let* ((lines (make-list 10 "line"))
+         (input (mapconcat #'identity lines "\n"))
+         (result (test-prepend-to-lines input "# "))
+         (result-lines (split-string result "\n")))
+    (should (= 10 (length result-lines)))
+    (should (cl-every (lambda (line) (string-prefix-p "# " line)) result-lines))))
+
+;;; Normal Cases - Various Prefixes
+
+(ert-deftest test-prepend-comment-marker ()
+  "Should prepend comment marker."
+  (let ((result (test-prepend-to-lines "line1\nline2" "// ")))
+    (should (string= result "// line1\n// line2"))))
+
+(ert-deftest test-prepend-hash-comment ()
+  "Should prepend hash comment."
+  (let ((result (test-prepend-to-lines "line1\nline2" "# ")))
+    (should (string= result "# line1\n# line2"))))
+
+(ert-deftest test-prepend-multi-char ()
+  "Should prepend multi-character prefix."
+  (let ((result (test-prepend-to-lines "line" "TODO: ")))
+    (should (string= result "TODO: line"))))
+
+(ert-deftest test-prepend-empty-prefix ()
+  "Should handle empty prefix."
+  (let ((result (test-prepend-to-lines "line1\nline2" "")))
+    (should (string= result "line1\nline2"))))
+
+;;; Boundary Cases - Trailing Newlines
+
+(ert-deftest test-prepend-with-trailing-newline ()
+  "Should preserve trailing newline."
+  (let ((result (test-prepend-to-lines "line1\nline2\n" "> ")))
+    (should (string= result "> line1\n> line2\n"))))
+
+(ert-deftest test-prepend-no-trailing-newline ()
+  "Should work without trailing newline."
+  (let ((result (test-prepend-to-lines "line1\nline2" "> ")))
+    (should (string= result "> line1\n> line2"))))
+
+(ert-deftest test-prepend-single-line-with-newline ()
+  "Should preserve trailing newline on single line."
+  (let ((result (test-prepend-to-lines "line\n" "> ")))
+    (should (string= result "> line\n"))))
+
+;;; Boundary Cases - Empty Lines
+
+(ert-deftest test-prepend-empty-line-between ()
+  "Should prepend to empty line between other lines."
+  (let ((result (test-prepend-to-lines "line1\n\nline3" "> ")))
+    (should (string= result "> line1\n> \n> line3"))))
+
+(ert-deftest test-prepend-only-empty-lines ()
+  "Should prepend to only empty lines."
+  (let ((result (test-prepend-to-lines "\n\n" "> ")))
+    (should (string= result "> \n> \n"))))
+
+(ert-deftest test-prepend-empty-first-line ()
+  "Should prepend to empty first line."
+  (let ((result (test-prepend-to-lines "\nline2\nline3" "> ")))
+    (should (string= result "> \n> line2\n> line3"))))
+
+;;; Boundary Cases - Whitespace
+
+(ert-deftest test-prepend-preserves-leading-whitespace ()
+  "Should preserve leading whitespace after prefix."
+  (let ((result (test-prepend-to-lines "  line1\n    line2" "// ")))
+    (should (string= result "//   line1\n//     line2"))))
+
+(ert-deftest test-prepend-preserves-trailing-whitespace ()
+  "Should preserve trailing whitespace on line."
+  (let ((result (test-prepend-to-lines "line1  \nline2  " "> ")))
+    (should (string= result "> line1  \n> line2  "))))
+
+(ert-deftest test-prepend-whitespace-only-line ()
+  "Should prepend to whitespace-only line."
+  (let ((result (test-prepend-to-lines "line1\n   \nline3" "> ")))
+    (should (string= result "> line1\n>    \n> line3"))))
+
+;;; Boundary Cases - Special Cases
+
+(ert-deftest test-prepend-empty-string ()
+  "Should handle empty string."
+  (let ((result (test-prepend-to-lines "" "> ")))
+    (should (string= result "> "))))
+
+(ert-deftest test-prepend-very-long-line ()
+  "Should prepend to very long line."
+  (let* ((long-line (make-string 1000 ?a))
+         (result (test-prepend-to-lines long-line "> ")))
+    (should (string-prefix-p "> " result))
+    (should (= (length result) 1002))))
+
+(ert-deftest test-prepend-with-existing-prefix ()
+  "Should prepend even if line already has the prefix."
+  (let ((result (test-prepend-to-lines "> line" "> ")))
+    (should (string= result "> > line"))))
+
+;;; Edge Cases - Special Characters in Prefix
+
+(ert-deftest test-prepend-newline-prefix ()
+  "Should prepend newline as prefix."
+  (let ((result (test-prepend-to-lines "line1\nline2" "\n")))
+    (should (string= result "\nline1\n\nline2"))))
+
+(ert-deftest test-prepend-tab-prefix ()
+  "Should prepend tab as prefix."
+  (let ((result (test-prepend-to-lines "line1\nline2" "\t")))
+    (should (string= result "\tline1\n\tline2"))))
+
+(ert-deftest test-prepend-quote-prefix ()
+  "Should prepend quote as prefix."
+  (let ((result (test-prepend-to-lines "line1\nline2" "\"")))
+    (should (string= result "\"line1\n\"line2"))))
+
+;;; Edge Cases - Common Use Cases
+
+(ert-deftest test-prepend-markdown-quote ()
+  "Should prepend markdown quote marker."
+  (let ((result (test-prepend-to-lines "quote text\nmore text" "> ")))
+    (should (string= result "> quote text\n> more text"))))
+
+(ert-deftest test-prepend-numbered-list ()
+  "Should prepend numbers (though simpler uses would vary the prefix)."
+  (let ((result (test-prepend-to-lines "item" "1. ")))
+    (should (string= result "1. item"))))
+
+(ert-deftest test-prepend-indentation ()
+  "Should prepend indentation spaces."
+  (let ((result (test-prepend-to-lines "code\nmore" "    ")))
+    (should (string= result "    code\n    more"))))
+
+(provide 'test-custom-text-enclose-prepend)
+;;; test-custom-text-enclose-prepend.el ends here