1 files changed, 149 insertions, 0 deletions
diff --git a/tests/test-coverage-core--parse-lcov.el b/tests/test-coverage-core--parse-lcov.el
new file mode 100644
index 00000000..a0a800ef
--- /dev/null
+++ b/tests/test-coverage-core--parse-lcov.el
@@ -0,0 +1,149 @@
+;;; test-coverage-core--parse-lcov.el --- Tests for cj/--coverage-parse-lcov -*- lexical-binding: t; -*-
+
+;;; Commentary:
+;; Unit tests for `cj/--coverage-parse-lcov', the pure helper that
+;; reads an LCOV file and returns a hash table of file → set of
+;; covered line numbers.
+;;
+;; LCOV format (the subset we care about):
+;;   SF:<source file>
+;;   DA:<line>,<hit count>
+;;   end_of_record
+;;
+;; A line counts as "covered" when its hit count is greater than zero.
+
+;;; Code:
+
+(require 'ert)
+
+(add-to-list 'load-path (expand-file-name "modules" user-emacs-directory))
+(require 'coverage-core)
+
+(defun test-coverage-parse-lcov--write-temp-lcov (content)
+  "Write CONTENT to a temp file and return its path.
+Caller is responsible for deleting the file."
+  (let ((file (make-temp-file "test-lcov-" nil ".info")))
+    (with-temp-file file
+      (insert content))
+    file))
+
+;;; Normal cases
+
+(ert-deftest test-coverage-parse-lcov-single-file-all-covered ()
+  "Normal: one file with every line hit > 0 returns all lines in the set."
+  (let* ((content "SF:/path/to/foo.el\nDA:10,1\nDA:11,2\nDA:12,3\nend_of_record\n")
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let* ((result (cj/--coverage-parse-lcov file))
+               (lines (gethash "/path/to/foo.el" result)))
+          (should (hash-table-p result))
+          (should (= 3 (hash-table-count lines)))
+          (should (gethash 10 lines))
+          (should (gethash 11 lines))
+          (should (gethash 12 lines)))
+      (delete-file file))))
+
+(ert-deftest test-coverage-parse-lcov-multiple-files ()
+  "Normal: multiple file records in one LCOV file are both parsed."
+  (let* ((content (concat "SF:/a.el\nDA:1,1\nDA:2,1\nend_of_record\n"
+                          "SF:/b.el\nDA:5,1\nend_of_record\n"))
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let ((result (cj/--coverage-parse-lcov file)))
+          (should (= 2 (hash-table-count result)))
+          (should (gethash "/a.el" result))
+          (should (gethash "/b.el" result)))
+      (delete-file file))))
+
+(ert-deftest test-coverage-parse-lcov-mixed-hits ()
+  "Normal: lines with hit count 0 are excluded; positive counts included."
+  (let* ((content "SF:/foo.el\nDA:1,0\nDA:2,1\nDA:3,0\nDA:4,5\nend_of_record\n")
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let* ((result (cj/--coverage-parse-lcov file))
+               (lines (gethash "/foo.el" result)))
+          (should (= 2 (hash-table-count lines)))
+          (should-not (gethash 1 lines))
+          (should (gethash 2 lines))
+          (should-not (gethash 3 lines))
+          (should (gethash 4 lines)))
+      (delete-file file))))
+
+;;; Boundary cases
+
+(ert-deftest test-coverage-parse-lcov-empty-file ()
+  "Boundary: empty LCOV file returns an empty hash table, not nil."
+  (let ((file (test-coverage-parse-lcov--write-temp-lcov "")))
+    (unwind-protect
+        (let ((result (cj/--coverage-parse-lcov file)))
+          (should (hash-table-p result))
+          (should (= 0 (hash-table-count result))))
+      (delete-file file))))
+
+(ert-deftest test-coverage-parse-lcov-file-with-spaces-in-path ()
+  "Boundary: filename with spaces is parsed as one key."
+  (let* ((content "SF:/my path/with spaces.el\nDA:1,1\nend_of_record\n")
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let ((result (cj/--coverage-parse-lcov file)))
+          (should (gethash "/my path/with spaces.el" result)))
+      (delete-file file))))
+
+(ert-deftest test-coverage-parse-lcov-extra-lcov-fields-ignored ()
+  "Boundary: LF/LH/BRDA/FN fields don't break parsing; only DA matters."
+  (let* ((content (concat "SF:/foo.el\n"
+                          "FN:10,some-function\n"
+                          "FNDA:1,some-function\n"
+                          "DA:10,1\n"
+                          "DA:11,1\n"
+                          "LF:2\n"
+                          "LH:2\n"
+                          "BRDA:10,0,0,1\n"
+                          "end_of_record\n"))
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let* ((result (cj/--coverage-parse-lcov file))
+               (lines (gethash "/foo.el" result)))
+          (should (= 2 (hash-table-count lines)))
+          (should (gethash 10 lines))
+          (should (gethash 11 lines)))
+      (delete-file file))))
+
+(ert-deftest test-coverage-parse-lcov-all-zero-hits ()
+  "Boundary: file with no covered lines returns an empty set for that file."
+  (let* ((content "SF:/foo.el\nDA:1,0\nDA:2,0\nend_of_record\n")
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let* ((result (cj/--coverage-parse-lcov file))
+               (lines (gethash "/foo.el" result)))
+          (should (hash-table-p lines))
+          (should (= 0 (hash-table-count lines))))
+      (delete-file file))))
+
+;;; Error cases
+
+(ert-deftest test-coverage-parse-lcov-missing-file-errors ()
+  "Error: nonexistent file signals a user-error naming the path."
+  (should-error (cj/--coverage-parse-lcov "/nonexistent/path/xyz.info")
+                :type 'user-error))
+
+(ert-deftest test-coverage-parse-lcov-malformed-da-line-skipped ()
+  "Error: malformed DA lines are skipped; parsing continues on the rest."
+  (let* ((content (concat "SF:/foo.el\n"
+                          "DA:not-a-number,1\n"
+                          "DA:10,1\n"
+                          "DA:\n"
+                          "DA:11,notanumber\n"
+                          "DA:12,2\n"
+                          "end_of_record\n"))
+         (file (test-coverage-parse-lcov--write-temp-lcov content)))
+    (unwind-protect
+        (let* ((result (cj/--coverage-parse-lcov file))
+               (lines (gethash "/foo.el" result)))
+          (should (= 2 (hash-table-count lines)))
+          (should (gethash 10 lines))
+          (should (gethash 12 lines)))
+      (delete-file file))))
+
+(provide 'test-coverage-core--parse-lcov)
+;;; test-coverage-core--parse-lcov.el ends here